def add_subgraph(self, info):
if not info.initialized:<EOL><INDENT>return<EOL><DEDENT>graph = self._request_graph(info.ui.control)<EOL>if graph is not None:<EOL><INDENT>subgraph = Subgraph()<EOL>retval = subgraph.edit_traits(parent = info.ui.control,<EOL>kind   = "<STR_LIT>")<EOL>if retval.result:<EOL><INDENT>graph.subgraphs.append(subgraph)<EOL><DEDENT><DEDENT>
Handles adding a Subgraph to the main graph.