parameters: (self, node_field_name)
return_statement: return node_field_name in self.node_fields
docstring: Return 'True' if the given node field exists.
  
          Examples:
          >>> model.node_field_exists('temperature')
docstring_summary: Return 'True' if the given node field exists.
docstring_tokens: Return True if the given node field exists .
function: def node_field_exists(self, node_field_name):
          """
          Return 'True' if the given node field exists.
  
          Examples:
          >>> model.node_field_exists('temperature')
  
          """
          return node_field_name in self.node_fields
function_tokens: def node_field_exists ( self , node_field_name ) : return node_field_name in self . node_fields