def add_node(self, node):
if (not node in self.node_links):<EOL><INDENT>self.node_links[node] = []<EOL>self.node_attr[node] = []<EOL>self.graph.add_node((node,'<STR_LIT:n>'))<EOL><DEDENT>else:<EOL><INDENT>raise AdditionError("<STR_LIT>" % node)<EOL><DEDENT>
Add given node to the hypergraph.

@attention: While nodes can be of any type, it's strongly recommended to use only numbers
and single-line strings as node identifiers if you intend to use write().

@type  node: node
@param node: Node identifier.