code: def get_operation_ast(document_ast, operation_name=None):
      operation = None
  
      for definition in document_ast.definitions:
          if isinstance(definition, ast.OperationDefinition):
              if not operation_name:
                  # If no operation name is provided, only return an Operation if it is the only one present in the
                  # document. This means that if we've encountered a second operation as we were iterating over the
                  # definitions in the document, there are more than one Operation defined, and we should return None.
                  if operation:
                      return None
  
                  operation = definition
  
              elif (
                  definition.name
                  and definition.name.value == operation_name
              ):
                  return definition
  
      return operation
  
label_desc: Use image node_id 1 for calling a global function with example usage: get_operation_ast(document_ast, operation_name) and returns: operation, None, definition