collections.py

from __future__ import unicode_literals, absolute_import
try:
    from future import standard_library
    standard_library.install_aliases()
except ModuleNotFoundError:
    pass
from builtins import str
from builtins import chr
from builtins import range
from builtins import object
import copy
import sys
if sys.version_info[1] >= 10:
    from collections.abc import Callable
    from collections import OrderedDict
else:
    from collections import OrderedDict, Callable


class OrderedDefaultDict(OrderedDict):

    """
    A fusion of Python's defaultdict and Python's OrderedDict.
    """
    def __init__(self, default_factory=None, *a, **kw):
        if (default_factory is not None and
           not isinstance(default_factory, Callable)):
            raise TypeError('first argument must be callable')
        OrderedDict.__init__(self, *a, **kw)
        self.default_factory = default_factory

    def __getitem__(self, key):
        try:
            return OrderedDict.__getitem__(self, key)
        except KeyError:
            return self.__missing__(key)

    def __missing__(self, key):
        if self.default_factory is None:
            raise KeyError(key)
        self[key] = value = self.default_factory()
        return value

    def __reduce__(self):
        if self.default_factory is None:
            args = tuple()
        else:
            args = self.default_factory,
        return type(self), args, None, None, self.items()

    def copy(self):
        return self.__copy__()

    def __copy__(self):
        return type(self)(self.default_factory, self)

    def __deepcopy__(self, memo):
        return type(self)(self.default_factory,
                          copy.deepcopy(self.items()))

    def __repr__(self):
        return 'OrderedDefaultDict(%s, %s)' % (self.default_factory,
                                               OrderedDict.__repr__(self))