solenv/gdb/six.py

   1 """Utilities for writing code that runs on Python 2 and 3"""
   2
   3 # Copyright (c) 2010-2013 Benjamin Peterson
   4 #
   5 # Permission is hereby granted, free of charge, to any person obtaining a copy
   6 # of this software and associated documentation files (the "Software"), to deal
   7 # in the Software without restriction, including without limitation the rights
   8 # to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
   9 # copies of the Software, and to permit persons to whom the Software is
  10 # furnished to do so, subject to the following conditions:
  11 #
  12 # The above copyright notice and this permission notice shall be included in all
  13 # copies or substantial portions of the Software.
  14 #
  15 # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16 # IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17 # FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  18 # AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19 # LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  20 # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  21 # SOFTWARE.
  22
  23 import operator
  24 import sys
  25 import types
  26
  27 __author__ = "Benjamin Peterson <benjamin@python.org>"
  28 __version__ = "1.4.1"
  29
  30
  31 # Useful for very coarse version differentiation.
  32 PY2 = sys.version_info[0] == 2
  33 PY3 = sys.version_info[0] == 3
  34
  35 if PY3:
  36     string_types = str,
  37     integer_types = int,
  38     class_types = type,
  39     text_type = str
  40     binary_type = bytes
  41
  42     MAXSIZE = sys.maxsize
  43 else:
  44     string_types = basestring,
  45     integer_types = (int, long)
  46     class_types = (type, types.ClassType)
  47     text_type = unicode
  48     binary_type = str
  49
  50     if sys.platform.startswith("java"):
  51         # Jython always uses 32 bits.
  52         MAXSIZE = int((1 << 31) - 1)
  53     else:
  54         # It's possible to have sizeof(long) != sizeof(Py_ssize_t).
  55         class X(object):
  56             def __len__(self):
  57                 return 1 << 31
  58         try:
  59             len(X())
  60         except OverflowError:
  61             # 32-bit
  62             MAXSIZE = int((1 << 31) - 1)
  63         else:
  64             # 64-bit
  65             MAXSIZE = int((1 << 63) - 1)
  66         del X
  67
  68
  69 def _add_doc(func, doc):
  70     """Add documentation to a function."""
  71     func.__doc__ = doc
  72
  73
  74 def _import_module(name):
  75     """Import module, returning the module after the last dot."""
  76     __import__(name)
  77     return sys.modules[name]
  78
  79
  80 class _LazyDescr(object):
  81
  82     def __init__(self, name):
  83         self.name = name
  84
  85     def __get__(self, obj, tp):
  86         result = self._resolve()
  87         setattr(obj, self.name, result)
  88         # This is a bit ugly, but it avoids running this again.
  89         delattr(tp, self.name)
  90         return result
  91
  92
  93 class MovedModule(_LazyDescr):
  94
  95     def __init__(self, name, old, new=None):
  96         super(MovedModule, self).__init__(name)
  97         if PY3:
  98             if new is None:
  99                 new = name
 100             self.mod = new
 101         else:
 102             self.mod = old
 103
 104     def _resolve(self):
 105         return _import_module(self.mod)
 106
 107
 108 class MovedAttribute(_LazyDescr):
 109
 110     def __init__(self, name, old_mod, new_mod, old_attr=None, new_attr=None):
 111         super(MovedAttribute, self).__init__(name)
 112         if PY3:
 113             if new_mod is None:
 114                 new_mod = name
 115             self.mod = new_mod
 116             if new_attr is None:
 117                 if old_attr is None:
 118                     new_attr = name
 119                 else:
 120                     new_attr = old_attr
 121             self.attr = new_attr
 122         else:
 123             self.mod = old_mod
 124             if old_attr is None:
 125                 old_attr = name
 126             self.attr = old_attr
 127
 128     def _resolve(self):
 129         module = _import_module(self.mod)
 130         return getattr(module, self.attr)
 131
 132
 133
 134 class _MovedItems(types.ModuleType):
 135     """Lazy loading of moved objects"""
 136
 137
 138 _moved_attributes = [
 139     MovedAttribute("cStringIO", "cStringIO", "io", "StringIO"),
 140     MovedAttribute("filter", "itertools", "builtins", "ifilter", "filter"),
 141     MovedAttribute("filterfalse", "itertools", "itertools", "ifilterfalse", "filterfalse"),
 142     MovedAttribute("input", "__builtin__", "builtins", "raw_input", "input"),
 143     MovedAttribute("map", "itertools", "builtins", "imap", "map"),
 144     MovedAttribute("range", "__builtin__", "builtins", "xrange", "range"),
 145     MovedAttribute("reload_module", "__builtin__", "imp", "reload"),
 146     MovedAttribute("reduce", "__builtin__", "functools"),
 147     MovedAttribute("StringIO", "StringIO", "io"),
 148     MovedAttribute("UserString", "UserString", "collections"),
 149     MovedAttribute("xrange", "__builtin__", "builtins", "xrange", "range"),
 150     MovedAttribute("zip", "itertools", "builtins", "izip", "zip"),
 151     MovedAttribute("zip_longest", "itertools", "itertools", "izip_longest", "zip_longest"),
 152
 153     MovedModule("builtins", "__builtin__"),
 154     MovedModule("configparser", "ConfigParser"),
 155     MovedModule("copyreg", "copy_reg"),
 156     MovedModule("http_cookiejar", "cookielib", "http.cookiejar"),
 157     MovedModule("http_cookies", "Cookie", "http.cookies"),
 158     MovedModule("html_entities", "htmlentitydefs", "html.entities"),
 159     MovedModule("html_parser", "HTMLParser", "html.parser"),
 160     MovedModule("http_client", "httplib", "http.client"),
 161     MovedModule("email_mime_multipart", "email.MIMEMultipart", "email.mime.multipart"),
 162     MovedModule("email_mime_text", "email.MIMEText", "email.mime.text"),
 163     MovedModule("email_mime_base", "email.MIMEBase", "email.mime.base"),
 164     MovedModule("BaseHTTPServer", "BaseHTTPServer", "http.server"),
 165     MovedModule("CGIHTTPServer", "CGIHTTPServer", "http.server"),
 166     MovedModule("SimpleHTTPServer", "SimpleHTTPServer", "http.server"),
 167     MovedModule("cPickle", "cPickle", "pickle"),
 168     MovedModule("queue", "Queue"),
 169     MovedModule("reprlib", "repr"),
 170     MovedModule("socketserver", "SocketServer"),
 171     MovedModule("tkinter", "Tkinter"),
 172     MovedModule("tkinter_dialog", "Dialog", "tkinter.dialog"),
 173     MovedModule("tkinter_filedialog", "FileDialog", "tkinter.filedialog"),
 174     MovedModule("tkinter_scrolledtext", "ScrolledText", "tkinter.scrolledtext"),
 175     MovedModule("tkinter_simpledialog", "SimpleDialog", "tkinter.simpledialog"),
 176     MovedModule("tkinter_tix", "Tix", "tkinter.tix"),
 177     MovedModule("tkinter_constants", "Tkconstants", "tkinter.constants"),
 178     MovedModule("tkinter_dnd", "Tkdnd", "tkinter.dnd"),
 179     MovedModule("tkinter_colorchooser", "tkColorChooser",
 180                 "tkinter.colorchooser"),
 181     MovedModule("tkinter_commondialog", "tkCommonDialog",
 182                 "tkinter.commondialog"),
 183     MovedModule("tkinter_tkfiledialog", "tkFileDialog", "tkinter.filedialog"),
 184     MovedModule("tkinter_font", "tkFont", "tkinter.font"),
 185     MovedModule("tkinter_messagebox", "tkMessageBox", "tkinter.messagebox"),
 186     MovedModule("tkinter_tksimpledialog", "tkSimpleDialog",
 187                 "tkinter.simpledialog"),
 188     MovedModule("urllib_parse", __name__ + ".moves.urllib_parse", "urllib.parse"),
 189     MovedModule("urllib_error", __name__ + ".moves.urllib_error", "urllib.error"),
 190     MovedModule("urllib", __name__ + ".moves.urllib", __name__ + ".moves.urllib"),
 191     MovedModule("urllib_robotparser", "robotparser", "urllib.robotparser"),
 192     MovedModule("winreg", "_winreg"),
 193 ]
 194 for attr in _moved_attributes:
 195     setattr(_MovedItems, attr.name, attr)
 196 del attr
 197
 198 moves = sys.modules[__name__ + ".moves"] = _MovedItems(__name__ + ".moves")
 199
 200
 201
 202 class Module_six_moves_urllib_parse(types.ModuleType):
 203     """Lazy loading of moved objects in six.moves.urllib_parse"""
 204
 205
 206 _urllib_parse_moved_attributes = [
 207     MovedAttribute("ParseResult", "urlparse", "urllib.parse"),
 208     MovedAttribute("parse_qs", "urlparse", "urllib.parse"),
 209     MovedAttribute("parse_qsl", "urlparse", "urllib.parse"),
 210     MovedAttribute("urldefrag", "urlparse", "urllib.parse"),
 211     MovedAttribute("urljoin", "urlparse", "urllib.parse"),
 212     MovedAttribute("urlparse", "urlparse", "urllib.parse"),
 213     MovedAttribute("urlsplit", "urlparse", "urllib.parse"),
 214     MovedAttribute("urlunparse", "urlparse", "urllib.parse"),
 215     MovedAttribute("urlunsplit", "urlparse", "urllib.parse"),
 216     MovedAttribute("quote", "urllib", "urllib.parse"),
 217     MovedAttribute("quote_plus", "urllib", "urllib.parse"),
 218     MovedAttribute("unquote", "urllib", "urllib.parse"),
 219     MovedAttribute("unquote_plus", "urllib", "urllib.parse"),
 220     MovedAttribute("urlencode", "urllib", "urllib.parse"),
 221 ]
 222 for attr in _urllib_parse_moved_attributes:
 223     setattr(Module_six_moves_urllib_parse, attr.name, attr)
 224 del attr
 225
 226 sys.modules[__name__ + ".moves.urllib_parse"] = Module_six_moves_urllib_parse(__name__ + ".moves.urllib_parse")
 227 sys.modules[__name__ + ".moves.urllib.parse"] = Module_six_moves_urllib_parse(__name__ + ".moves.urllib.parse")
 228
 229
 230 class Module_six_moves_urllib_error(types.ModuleType):
 231     """Lazy loading of moved objects in six.moves.urllib_error"""
 232
 233
 234 _urllib_error_moved_attributes = [
 235     MovedAttribute("URLError", "urllib2", "urllib.error"),
 236     MovedAttribute("HTTPError", "urllib2", "urllib.error"),
 237     MovedAttribute("ContentTooShortError", "urllib", "urllib.error"),
 238 ]
 239 for attr in _urllib_error_moved_attributes:
 240     setattr(Module_six_moves_urllib_error, attr.name, attr)
 241 del attr
 242
 243 sys.modules[__name__ + ".moves.urllib_error"] = Module_six_moves_urllib_error(__name__ + ".moves.urllib_error")
 244 sys.modules[__name__ + ".moves.urllib.error"] = Module_six_moves_urllib_error(__name__ + ".moves.urllib.error")
 245
 246
 247 class Module_six_moves_urllib_request(types.ModuleType):
 248     """Lazy loading of moved objects in six.moves.urllib_request"""
 249
 250
 251 _urllib_request_moved_attributes = [
 252     MovedAttribute("urlopen", "urllib2", "urllib.request"),
 253     MovedAttribute("install_opener", "urllib2", "urllib.request"),
 254     MovedAttribute("build_opener", "urllib2", "urllib.request"),
 255     MovedAttribute("pathname2url", "urllib", "urllib.request"),
 256     MovedAttribute("url2pathname", "urllib", "urllib.request"),
 257     MovedAttribute("getproxies", "urllib", "urllib.request"),
 258     MovedAttribute("Request", "urllib2", "urllib.request"),
 259     MovedAttribute("OpenerDirector", "urllib2", "urllib.request"),
 260     MovedAttribute("HTTPDefaultErrorHandler", "urllib2", "urllib.request"),
 261     MovedAttribute("HTTPRedirectHandler", "urllib2", "urllib.request"),
 262     MovedAttribute("HTTPCookieProcessor", "urllib2", "urllib.request"),
 263     MovedAttribute("ProxyHandler", "urllib2", "urllib.request"),
 264     MovedAttribute("BaseHandler", "urllib2", "urllib.request"),
 265     MovedAttribute("HTTPPasswordMgr", "urllib2", "urllib.request"),
 266     MovedAttribute("HTTPPasswordMgrWithDefaultRealm", "urllib2", "urllib.request"),
 267     MovedAttribute("AbstractBasicAuthHandler", "urllib2", "urllib.request"),
 268     MovedAttribute("HTTPBasicAuthHandler", "urllib2", "urllib.request"),
 269     MovedAttribute("ProxyBasicAuthHandler", "urllib2", "urllib.request"),
 270     MovedAttribute("AbstractDigestAuthHandler", "urllib2", "urllib.request"),
 271     MovedAttribute("HTTPDigestAuthHandler", "urllib2", "urllib.request"),
 272     MovedAttribute("ProxyDigestAuthHandler", "urllib2", "urllib.request"),
 273     MovedAttribute("HTTPHandler", "urllib2", "urllib.request"),
 274     MovedAttribute("HTTPSHandler", "urllib2", "urllib.request"),
 275     MovedAttribute("FileHandler", "urllib2", "urllib.request"),
 276     MovedAttribute("FTPHandler", "urllib2", "urllib.request"),
 277     MovedAttribute("CacheFTPHandler", "urllib2", "urllib.request"),
 278     MovedAttribute("UnknownHandler", "urllib2", "urllib.request"),
 279     MovedAttribute("HTTPErrorProcessor", "urllib2", "urllib.request"),
 280     MovedAttribute("urlretrieve", "urllib", "urllib.request"),
 281     MovedAttribute("urlcleanup", "urllib", "urllib.request"),
 282     MovedAttribute("URLopener", "urllib", "urllib.request"),
 283     MovedAttribute("FancyURLopener", "urllib", "urllib.request"),
 284 ]
 285 for attr in _urllib_request_moved_attributes:
 286     setattr(Module_six_moves_urllib_request, attr.name, attr)
 287 del attr
 288
 289 sys.modules[__name__ + ".moves.urllib_request"] = Module_six_moves_urllib_request(__name__ + ".moves.urllib_request")
 290 sys.modules[__name__ + ".moves.urllib.request"] = Module_six_moves_urllib_request(__name__ + ".moves.urllib.request")
 291
 292
 293 class Module_six_moves_urllib_response(types.ModuleType):
 294     """Lazy loading of moved objects in six.moves.urllib_response"""
 295
 296
 297 _urllib_response_moved_attributes = [
 298     MovedAttribute("addbase", "urllib", "urllib.response"),
 299     MovedAttribute("addclosehook", "urllib", "urllib.response"),
 300     MovedAttribute("addinfo", "urllib", "urllib.response"),
 301     MovedAttribute("addinfourl", "urllib", "urllib.response"),
 302 ]
 303 for attr in _urllib_response_moved_attributes:
 304     setattr(Module_six_moves_urllib_response, attr.name, attr)
 305 del attr
 306
 307 sys.modules[__name__ + ".moves.urllib_response"] = Module_six_moves_urllib_response(__name__ + ".moves.urllib_response")
 308 sys.modules[__name__ + ".moves.urllib.response"] = Module_six_moves_urllib_response(__name__ + ".moves.urllib.response")
 309
 310
 311 class Module_six_moves_urllib_robotparser(types.ModuleType):
 312     """Lazy loading of moved objects in six.moves.urllib_robotparser"""
 313
 314
 315 _urllib_robotparser_moved_attributes = [
 316     MovedAttribute("RobotFileParser", "robotparser", "urllib.robotparser"),
 317 ]
 318 for attr in _urllib_robotparser_moved_attributes:
 319     setattr(Module_six_moves_urllib_robotparser, attr.name, attr)
 320 del attr
 321
 322 sys.modules[__name__ + ".moves.urllib_robotparser"] = Module_six_moves_urllib_robotparser(__name__ + ".moves.urllib_robotparser")
 323 sys.modules[__name__ + ".moves.urllib.robotparser"] = Module_six_moves_urllib_robotparser(__name__ + ".moves.urllib.robotparser")
 324
 325
 326 class Module_six_moves_urllib(types.ModuleType):
 327     """Create a six.moves.urllib namespace that resembles the Python 3 namespace"""
 328     parse = sys.modules[__name__ + ".moves.urllib_parse"]
 329     error = sys.modules[__name__ + ".moves.urllib_error"]
 330     request = sys.modules[__name__ + ".moves.urllib_request"]
 331     response = sys.modules[__name__ + ".moves.urllib_response"]
 332     robotparser = sys.modules[__name__ + ".moves.urllib_robotparser"]
 333
 334
 335 sys.modules[__name__ + ".moves.urllib"] = Module_six_moves_urllib(__name__ + ".moves.urllib")
 336
 337
 338 def add_move(move):
 339     """Add an item to six.moves."""
 340     setattr(_MovedItems, move.name, move)
 341
 342
 343 def remove_move(name):
 344     """Remove item from six.moves."""
 345     try:
 346         delattr(_MovedItems, name)
 347     except AttributeError:
 348         try:
 349             del moves.__dict__[name]
 350         except KeyError:
 351             raise AttributeError("no such move, %r" % (name,))
 352
 353
 354 if PY3:
 355     _meth_func = "__func__"
 356     _meth_self = "__self__"
 357
 358     _func_closure = "__closure__"
 359     _func_code = "__code__"
 360     _func_defaults = "__defaults__"
 361     _func_globals = "__globals__"
 362
 363     _iterkeys = "keys"
 364     _itervalues = "values"
 365     _iteritems = "items"
 366     _iterlists = "lists"
 367 else:
 368     _meth_func = "im_func"
 369     _meth_self = "im_self"
 370
 371     _func_closure = "func_closure"
 372     _func_code = "func_code"
 373     _func_defaults = "func_defaults"
 374     _func_globals = "func_globals"
 375
 376     _iterkeys = "iterkeys"
 377     _itervalues = "itervalues"
 378     _iteritems = "iteritems"
 379     _iterlists = "iterlists"
 380
 381
 382 try:
 383     advance_iterator = next
 384 except NameError:
 385     def advance_iterator(it):
 386         return it.next()
 387 next = advance_iterator
 388
 389
 390 try:
 391     callable = callable
 392 except NameError:
 393     def callable(obj):
 394         return any("__call__" in klass.__dict__ for klass in type(obj).__mro__)
 395
 396
 397 if PY3:
 398     def get_unbound_function(unbound):
 399         return unbound
 400
 401     create_bound_method = types.MethodType
 402
 403     Iterator = object
 404 else:
 405     def get_unbound_function(unbound):
 406         return unbound.im_func
 407
 408     def create_bound_method(func, obj):
 409         return types.MethodType(func, obj, obj.__class__)
 410
 411     class Iterator(object):
 412
 413         def next(self):
 414             return type(self).__next__(self)
 415
 416     callable = callable
 417 _add_doc(get_unbound_function,
 418          """Get the function out of a possibly unbound function""")
 419
 420
 421 get_method_function = operator.attrgetter(_meth_func)
 422 get_method_self = operator.attrgetter(_meth_self)
 423 get_function_closure = operator.attrgetter(_func_closure)
 424 get_function_code = operator.attrgetter(_func_code)
 425 get_function_defaults = operator.attrgetter(_func_defaults)
 426 get_function_globals = operator.attrgetter(_func_globals)
 427
 428
 429 def iterkeys(d, **kw):
 430     """Return an iterator over the keys of a dictionary."""
 431     return iter(getattr(d, _iterkeys)(**kw))
 432
 433 def itervalues(d, **kw):
 434     """Return an iterator over the values of a dictionary."""
 435     return iter(getattr(d, _itervalues)(**kw))
 436
 437 def iteritems(d, **kw):
 438     """Return an iterator over the (key, value) pairs of a dictionary."""
 439     return iter(getattr(d, _iteritems)(**kw))
 440
 441 def iterlists(d, **kw):
 442     """Return an iterator over the (key, [values]) pairs of a dictionary."""
 443     return iter(getattr(d, _iterlists)(**kw))
 444
 445
 446 if PY3:
 447     def b(s):
 448         return s.encode("latin-1")
 449     def u(s):
 450         return s
 451     unichr = chr
 452     if sys.version_info[1] <= 1:
 453         def int2byte(i):
 454             return bytes((i,))
 455     else:
 456         # This is about 2x faster than the implementation above on 3.2+
 457         int2byte = operator.methodcaller("to_bytes", 1, "big")
 458     byte2int = operator.itemgetter(0)
 459     indexbytes = operator.getitem
 460     iterbytes = iter
 461     import io
 462     StringIO = io.StringIO
 463     BytesIO = io.BytesIO
 464 else:
 465     def b(s):
 466         return s
 467     def u(s):
 468         return unicode(s, "unicode_escape")
 469     unichr = unichr
 470     int2byte = chr
 471     def byte2int(bs):
 472         return ord(bs[0])
 473     def indexbytes(buf, i):
 474         return ord(buf[i])
 475     def iterbytes(buf):
 476         return (ord(byte) for byte in buf)
 477     import StringIO
 478     StringIO = BytesIO = StringIO.StringIO
 479 _add_doc(b, """Byte literal""")
 480 _add_doc(u, """Text literal""")
 481
 482
 483 if PY3:
 484     import builtins
 485     exec_ = getattr(builtins, "exec")
 486
 487
 488     def reraise(tp, value, tb=None):
 489         if value.__traceback__ is not tb:
 490             raise value.with_traceback(tb)
 491         raise value
 492
 493
 494     print_ = getattr(builtins, "print")
 495     del builtins
 496
 497 else:
 498     def exec_(_code_, _globs_=None, _locs_=None):
 499         """Execute code in a namespace."""
 500         if _globs_ is None:
 501             frame = sys._getframe(1)
 502             _globs_ = frame.f_globals
 503             if _locs_ is None:
 504                 _locs_ = frame.f_locals
 505             del frame
 506         elif _locs_ is None:
 507             _locs_ = _globs_
 508         exec("""exec _code_ in _globs_, _locs_""")
 509
 510
 511     exec_("""def reraise(tp, value, tb=None):
 512     raise tp, value, tb
 513 """)
 514
 515
 516     def print_(*args, **kwargs):
 517         """The new-style print function."""
 518         fp = kwargs.pop("file", sys.stdout)
 519         if fp is None:
 520             return
 521         def write(data):
 522             if not isinstance(data, basestring):
 523                 data = str(data)
 524             fp.write(data)
 525         want_unicode = False
 526         sep = kwargs.pop("sep", None)
 527         if sep is not None:
 528             if isinstance(sep, unicode):
 529                 want_unicode = True
 530             elif not isinstance(sep, str):
 531                 raise TypeError("sep must be None or a string")
 532         end = kwargs.pop("end", None)
 533         if end is not None:
 534             if isinstance(end, unicode):
 535                 want_unicode = True
 536             elif not isinstance(end, str):
 537                 raise TypeError("end must be None or a string")
 538         if kwargs:
 539             raise TypeError("invalid keyword arguments to print()")
 540         if not want_unicode:
 541             for arg in args:
 542                 if isinstance(arg, unicode):
 543                     want_unicode = True
 544                     break
 545         if want_unicode:
 546             newline = unicode("\n")
 547             space = unicode(" ")
 548         else:
 549             newline = "\n"
 550             space = " "
 551         if sep is None:
 552             sep = space
 553         if end is None:
 554             end = newline
 555         for i, arg in enumerate(args):
 556             if i:
 557                 write(sep)
 558             write(arg)
 559         write(end)
 560
 561 _add_doc(reraise, """Reraise an exception.""")
 562
 563
 564 def with_metaclass(meta, *bases):
 565     """Create a base class with a metaclass."""
 566     return meta("NewBase", bases, {})
 567
 568 def add_metaclass(metaclass):
 569     """Class decorator for creating a class with a metaclass."""
 570     def wrapper(cls):
 571         orig_vars = cls.__dict__.copy()
 572         orig_vars.pop('__dict__', None)
 573         orig_vars.pop('__weakref__', None)
 574         for slots_var in orig_vars.get('__slots__', ()):
 575             orig_vars.pop(slots_var)
 576         return metaclass(cls.__name__, cls.__bases__, orig_vars)
 577     return wrapper