code: def duplicate_variable_message(operation_name):
      return 'There can be only one variable named "{}".'.format(
          operation_name
      )
  
file_path: wandb/wandb/vendor/graphql-core-1.1/wandb_graphql/validation/rules/unique_variable_names.py
imports: from ...error import GraphQLError
  from .base import ValidationRule
label_desc: Use image node_id 4 for calling the UniqueVariableNames obj's underlying member method code with example usage: obj.duplicate_variable_message(operation_name) and returns: str