def addDependency(self, From, to, label, type, description = None):
#if self.isInvalidEdge(From, to):
# return
fromToken = self._map[From]
toToken = self._map[to]
edge = Edge(fromToken, toToken, label, type, Edge.RenderType.dependency)
if description is not None:
edge.description = description
self._edges.append(edge)
