parameters: (self, node)
return_statement: return self
docstring: Add a node to the cluster.
  
          @type  node: pGRAPH Node
          @param node: Node to add to cluster
docstring_summary: Add a node to the cluster.
docstring_tokens: Add a node to the cluster .
function: def add_node (self, node):
          '''
          Add a node to the cluster.
  
          @type  node: pGRAPH Node
          @param node: Node to add to cluster
          '''
  
          self.nodes.append(node)
  
          return self
function_tokens: def add_node ( self , node ) : self . nodes . append ( node ) return self