def getSharedFace(firstEdge, faces, secondEdge):
 for firstEdgeFaceIndex in firstEdge.faceIndexes:
  for secondEdgeFaceIndex in secondEdge.faceIndexes:
   if (firstEdgeFaceIndex == secondEdgeFaceIndex):
    return faces[firstEdgeFaceIndex]
 return None

def getSharedFace ( firstEdge , faces , secondEdge ) : for firstEdgeFaceIndex in firstEdge . faceIndexes : for secondEdgeFaceIndex in secondEdge . faceIndexes : if ( firstEdgeFaceIndex == secondEdgeFaceIndex ) : return faces [ firstEdgeFaceIndex ] return None
get the face which is shared by two edges .