def _get_signature(call: Callable[..., Any]) -> inspect.Signature:
    if sys.version_info >= (3, 10):
        try:
            signature = inspect.signature(call, eval_str=True)
        except NameError:
            # Handle type annotations with if TYPE_CHECKING, not used by FastAPI
            # e.g. dependency return types
            signature = inspect.signature(call)
    else:

import http.client
import inspect
import warnings
from collections.abc import Sequence
from typing import Any, Optional, Union, cast

from fastapi import routing
from fastapi._compat import (
    ModelField,
    Undefined,
    get_compat_model_name_map,
    get_definitions,
    get_schema_from_model_field,
    lenient_issubclass,
)
from fastapi.datastructures import DefaultPlaceholder
from fastapi.dependencies.models import Dependant

        return _endpoint_context_cache[func_id]

    try:
        ctx: EndpointContext = {}

        if (source_file := inspect.getsourcefile(func)) is not None:
            ctx["file"] = source_file
        if (line_number := inspect.getsourcelines(func)[1]) is not None:
            ctx["line"] = line_number
        if (func_name := getattr(func, "__name__", None)) is not None:

* 🐛 Reenable `allow_arbitrary_types` when only 1 argument is used on the API endpoint. PR [#13694](https://github.com/fastapi/fastapi/pull/13694) by [@rmawatson](https://github.com/rmawatson).
* 🐛 Fix `inspect.getcoroutinefunction()` can break testing with `unittest.mock.patch()`. PR [#14022](https://github.com/fastapi/fastapi/pull/14022) by [@secrett2633](https://github.com/secrett2633).

### Refactors