code: def on_name(self, node):    # ('id', 'ctx')
          
          ctx = node.ctx.__class__
          if ctx in (ast.Param, ast.Del):
              return str(node.id)
          else:
              if node.id in self.symtable:
                  return self.symtable[node.id]
              else:
                  msg = "name '%s' is not defined" % node.id
                  self.raise_exception(node, exc=NameError, msg=msg)
docs: Name node.