def add_nodes(self, nodes, xtras=None):
for node, xtra in zip(nodes, (xtras or repeat(None))):<EOL><INDENT>self.add_node(node, xtra)<EOL><DEDENT>
Adds **node objects** to the graph.

Arguments:

  - nodes(iterable) Sequence of **node objects** to be added to the 
    ``DictGraph``

  - xtras(iterable) [default: ``None``] Sequence of ``Node.xtra`` 
    dictionaries corresponding to the **node objects** being added. 
    See: ``Graph.add_node``.