langchain/langchain/formatting.py
2022-10-24 14:51:15 -07:00

33 lines
981 B
Python

"""Utilities for formatting strings."""
from string import Formatter
from typing import Any, Mapping, Sequence, Union
class StrictFormatter(Formatter):
"""A subclass of formatter that checks for extra keys."""
def check_unused_args(
self,
used_args: Sequence[Union[int, str]],
args: Sequence,
kwargs: Mapping[str, Any],
) -> None:
"""Check to see if extra parameters are passed."""
extra = set(kwargs).difference(used_args)
if extra:
raise KeyError(extra)
def vformat(
self, format_string: str, args: Sequence, kwargs: Mapping[str, Any]
) -> str:
"""Check that no arguments are provided."""
if len(args) > 0:
raise ValueError(
"No arguments should be provided, "
"everything should be passed as keyword arguments."
)
return super().vformat(format_string, args, kwargs)
formatter = StrictFormatter()