(dictionary, edge, elem)
If ``edge`` is not in ``dictionary``, adds ``edge`` to the
        dictionary and sets its value to ``[elem]``.  Otherwise
        appends ``elem`` to the value of existing entry.

        Note that edges are undirected, thus `(A, B) = (B, A)`.
If ``edge`` is not in ``dictionary``, adds ``edge`` to the
        dictionary and sets its value to ``[elem]``.  Otherwise
        appends ``elem`` to the value of existing entry.
If edge is not in dictionary adds edge to the dictionary and sets its value to [ elem ] . Otherwise appends elem to the value of existing entry .
def _add_edge_append(dictionary, edge, elem):
        """
        If ``edge`` is not in ``dictionary``, adds ``edge`` to the
        dictionary and sets its value to ``[elem]``.  Otherwise
        appends ``elem`` to the value of existing entry.

        Note that edges are undirected, thus `(A, B) = (B, A)`.
        """
        if edge in dictionary:
            dictionary[edge].append(elem)
        else:
            dictionary[edge] = [elem]
def _add_edge_append ( dictionary , edge , elem ) : if edge in dictionary : dictionary [ edge ] . append ( elem ) else : dictionary [ edge ] = [ elem ]