def getVertex(self, _id):
try:<EOL><INDENT>node = self.neograph.nodes.get(_id)<EOL><DEDENT>except client.NotFoundError:<EOL><INDENT>return None<EOL><DEDENT>return Vertex(node)<EOL>
Retrieves an existing vertex from the graph
        @params _id: Node unique identifier

        @returns The requested Vertex or None