dict method in __builtin__.pi

Question

I try to understand builtin.pi file.

read into this file about dict class:

class dict(object):
  """ dict() -> new empty dictionary
  dict(mapping) -> new dictionary initialized from a mapping object's
      (key, value) pairs
  dict(iterable) -> new dictionary initialized as if via:
      d = {}
      for k, v in iterable:
          d[k] = v
  dict(**kwargs) -> new dictionary initialized with the name=value pairs
      in the keyword argument list.  For example:  dict(one=1, two=2) """

  def __init__(self):
    """ x.__init__(...) initializes x; see help(type(x)) for signature """
    return {}

  def clear(self):
    """ D.clear() -> None.  Remove all items from D. """
    return None

  def copy(self):
    """ D.copy() -> a shallow copy of D """
    return None

  def fromkeys(self, S, v=None):
    """ dict.fromkeys(S[,v]) -> New dict with keys from S and values equal to v.
    v defaults to None. """
    return {}

  def get(self, k, d=None):
    """ D.get(k[,d]) -> D[k] if k in D, else d.  d defaults to None. """
    return None

for example. if i calls dict_object.get(key), my python IDE points me to the get method, but the get method inside dict class always returns None. how does this work. thanks