text: # Backport of OrderedDict() class that runs on Python 2.4, 2.5, 2.6, 2.7 and pypy.
  # Passes Python2.7's test suite and incorporates all the latest updates.
  # Copyright 2009 Raymond Hettinger, released under the MIT License.
  # http://code.activestate.com/recipes/576693/
  try:
      from thread import get_ident as _get_ident
  except ImportError:
      from dummy_thread import get_ident as _get_ident
  
  try:
      from _abcoll import KeysView, ValuesView, ItemsView
  except ImportError:
      pass
  
  
  class OrderedDict(dict):
      "Dictionary that remembers insertion order"
      # An inherited dict maps keys to values.
      # The inherited dict provides __getitem__, __len__, __contains__, and get.
      # The remaining methods are order-aware.
      # Big-O running times for all methods are the same as for regular dictionaries.
  
      # The internal self.__map dictionary maps keys to links in a doubly linked list.
      # The circular doubly linked list starts and ends with a sentinel element.
      # The sentinel element never gets deleted (this simplifies the algorithm).
      # Each link is stored as a list of length three:  [PREV, NEXT, KEY].
  
      def __init__(self, *args, **kwds):
          """Initialize an ordered dictionary.  Signature is the same as for
          regular dictionaries, but keyword arguments are not recommended
          because their insertion order is arbitrary.
  
          """
          if len(args) > 1:
              raise TypeError("expected at most 1 arguments, got %d" % len(args))
          try:
              self.__root
          except AttributeError:
              self.__root = root = []  # sentinel node
              root[:] = [root, root, None]
              self.__map = {}
          self.__update(*args, **kwds)
  
      def __setitem__(self, key, value, dict_setitem=dict.__setitem__):
          "od.__setitem__(i, y) <==> od[i]=y"
          # Setting a new item creates a new link which goes at the end of the linked
          # list, and the inherited dictionary is updated with the new key/value pair.
          if key not in self:
              root = self.__root
              last = root[0]
              last[1] = root[0] = self.__map[key] = [last, root, key]
          dict_setitem(self, key, value)
  
      def __delitem__(self, key, dict_delitem=dict.__delitem__):
          "od.__delitem__(y) <==> del od[y]"
          # Deleting an existing item uses self.__map to find the link which is
          # then removed by updating the links in the predecessor and successor nodes.
          dict_delitem(self, key)
          link_prev, link_next, key = self.__map.pop(key)
          link_prev[1] = link_next
          link_next[0] = link_prev
  
      def __iter__(self):
          "od.__iter__() <==> iter(od)"
          root = self.__root
          curr = root[1]
          while curr is not root:
              yield curr[2]
              curr = curr[1]
  
      def __reversed__(self):
          "od.__reversed__() <==> reversed(od)"
          root = self.__root
          curr = root[0]
          while curr is not root:
              yield curr[2]
              curr = curr[0]
  
      def clear(self):
          "od.clear() -> None.  Remove all items from od."
          try:
              for node in self.__map.itervalues():
                  del node[:]
              root = self.__root
              root[:] = [root, root, None]
              self.__map.clear()
          except AttributeError:
              pass
          dict.clear(self)
  
      def popitem(self, last=True):
          """od.popitem() -> (k, v), return and remove a (key, value) pair.
          Pairs are returned in LIFO order if last is true or FIFO order if false.
  
          """
          if not self:
              raise KeyError("dictionary is empty")
          root = self.__root
          if last:
              link = root[0]
              link_prev = link[0]
              link_prev[1] = root
              root[0] = link_prev
          else:
              link = root[1]
              link_next = link[1]
              root[1] = link_next
              link_next[0] = root
          key = link[2]
          del self.__map[key]
          value = dict.pop(self, key)
          return key, value
  
      # -- the following methods do not depend on the internal structure --
  
      def keys(self):
          "od.keys() -> list of keys in od"
          return list(self)
  
      def values(self):
          "od.values() -> list of values in od"
          return [self[key] for key in self]
  
      def items(self):
          "od.items() -> list of (key, value) pairs in od"
          return [(key, self[key]) for key in self]
  
      def iterkeys(self):
          "od.iterkeys() -> an iterator over the keys in od"
          return iter(self)
  
      def itervalues(self):
          "od.itervalues -> an iterator over the values in od"
          for k in self:
              yield self[k]
  
      def iteritems(self):
          "od.iteritems -> an iterator over the (key, value) items in od"
          for k in self:
              yield (k, self[k])
  
      def update(*args, **kwds):
          """od.update(E, **F) -> None.  Update od from dict/iterable E and F.
  
          If E is a dict instance, does:           for k in E: od[k] = E[k]
          If E has a .keys() method, does:         for k in E.keys(): od[k] = E[k]
          Or if E is an iterable of items, does:   for k, v in E: od[k] = v
          In either case, this is followed by:     for k, v in F.items(): od[k] = v
  
          """
          if len(args) > 2:
              raise TypeError(
                  "update() takes at most 2 positional "
                  "arguments (%d given)" % (len(args),)
              )
          elif not args:
              raise TypeError("update() takes at least 1 argument (0 given)")
          self = args[0]
          # Make progressively weaker assumptions about "other"
          other = ()
          if len(args) == 2:
              other = args[1]
          if isinstance(other, dict):
              for key in other:
                  self[key] = other[key]
          elif hasattr(other, "keys"):
              for key in other.keys():
                  self[key] = other[key]
          else:
              for key, value in other:
                  self[key] = value
          for key, value in kwds.items():
              self[key] = value
  
      __update = update  # let subclasses override update without breaking __init__
  
      __marker = object()
  
      def pop(self, key, default=__marker):
          """od.pop(k[,d]) -> v, remove specified key and return the corresponding value.
          If key is not found, d is returned if given, otherwise KeyError is raised.
  
          """
          if key in self:
              result = self[key]
              del self[key]
              return result
          if default is self.__marker:
              raise KeyError(key)
          return default
  
      def setdefault(self, key, default=None):
          "od.setdefault(k[,d]) -> od.get(k,d), also set od[k]=d if k not in od"
          if key in self:
              return self[key]
          self[key] = default
          return default
  
      def __repr__(self, _repr_running={}):
          "od.__repr__() <==> repr(od)"
          call_key = id(self), _get_ident()
          if call_key in _repr_running:
              return "..."
          _repr_running[call_key] = 1
          try:
              if not self:
                  return "%s()" % (self.__class__.__name__,)
              return "%s(%r)" % (self.__class__.__name__, self.items())
          finally:
              del _repr_running[call_key]
  
      def __reduce__(self):
          "Return state information for pickling"
          items = [[k, self[k]] for k in self]
          inst_dict = vars(self).copy()
          for k in vars(OrderedDict()):
              inst_dict.pop(k, None)
          if inst_dict:
              return (self.__class__, (items,), inst_dict)
          return self.__class__, (items,)
  
      def copy(self):
          "od.copy() -> a shallow copy of od"
          return self.__class__(self)
  
      @classmethod
      def fromkeys(cls, iterable, value=None):
          """OD.fromkeys(S[, v]) -> New ordered dictionary with keys from S
          and values equal to v (which defaults to None).
  
          """
          d = cls()
          for key in iterable:
              d[key] = value
          return d
  
      def __eq__(self, other):
          """od.__eq__(y) <==> od==y.  Comparison to another OD is order-sensitive
          while comparison to a regular mapping is order-insensitive.
  
          """
          if isinstance(other, OrderedDict):
              return len(self) == len(other) and self.items() == other.items()
          return dict.__eq__(self, other)
  
      def __ne__(self, other):
          return not self == other
  
      # -- the following methods are only used in Python 2.7 --
  
      def viewkeys(self):
          "od.viewkeys() -> a set-like object providing a view on od's keys"
          return KeysView(self)
  
      def viewvalues(self):
          "od.viewvalues() -> an object providing a view on od's values"
          return ValuesView(self)
  
      def viewitems(self):
          "od.viewitems() -> a set-like object providing a view on od's items"
          return ItemsView(self)
  