code: def get_node_by_id(self, node_id):
          
          tmp_nodes = self.diagram_graph.nodes(data=True)
          for node in tmp_nodes:
              if node[0] == node_id:
                  return node
docs: Gets a node with requested ID.
          Returns a tuple, where first value is node ID, second - a dictionary of all node attributes.
  
          :param node_id: string with ID of node.