(edge1, edge2)
return (edge1 - intersection) | (edge2 - intersection)
If ``edge1`` and ``edge2`` have precisely one common endpoint,
        returns an edge which would form a triangle with ``edge1`` and
        ``edge2``.

        If ``edge1`` and ``edge2`` don't have a common endpoint,
        returns ``None``.

        If ``edge1`` and ``edge`` are the same edge, returns ``None``.
If ``edge1`` and ``edge2`` have precisely one common endpoint,
        returns an edge which would form a triangle with ``edge1`` and
        ``edge2``.
If edge1 and edge2 have precisely one common endpoint returns an edge which would form a triangle with edge1 and edge2 .
def _juxtapose_edges(edge1, edge2):
        """
        If ``edge1`` and ``edge2`` have precisely one common endpoint,
        returns an edge which would form a triangle with ``edge1`` and
        ``edge2``.

        If ``edge1`` and ``edge2`` don't have a common endpoint,
        returns ``None``.

        If ``edge1`` and ``edge`` are the same edge, returns ``None``.
        """
        intersection = edge1 & edge2
        if len(intersection) != 1:
            # The edges either have no common points or are equal.
            return None

        # The edges have a common endpoint.  Extract the different
        # endpoints and set up the new edge.
        return (edge1 - intersection) | (edge2 - intersection)
def _juxtapose_edges ( edge1 , edge2 ) : intersection = edge1 & edge2 if len ( intersection ) != 1 : # The edges either have no common points or are equal. return None # The edges have a common endpoint.  Extract the different # endpoints and set up the new edge. return ( edge1 - intersection ) | ( edge2 - intersection )