parameters: (self, node)
docstring: Add *node* to the graph.  This is necessary before adding any
          edges from/to the node.  *node* can be any hashable object.
docstring_summary: Add *node* to the graph.  This is necessary before adding any
          edges from/to the node.  *node* can be any hashable object.
docstring_tokens: Add * node * to the graph . This is necessary before adding any edges from / to the node . * node * can be any hashable object .
function: def add_node(self, node):
          """
          Add *node* to the graph.  This is necessary before adding any
          edges from/to the node.  *node* can be any hashable object.
          """
          self._nodes.add(node)
function_tokens: def add_node ( self , node ) : self . _nodes . add ( node )