Caching a function with a DataFrame parameter doesn't work

[viksuper555]

When you cache a function, that has a parameter, which has a default value of a DataFrame raises an Exception.

Minimal reproducible example:

@cache.memoize()
def foo(df=pd.DataFrame(), **kwargs):
print('Not reached')

Traceback:

ValueError: The truth value of a DataFrame is ambiguous. Use a.empty, a.bool(), a.item(), a.any() or a.all().
File "init.py", line 839, in decorated_function
cache_key = decorated_function.make_cache_key(f, *args, **kwargs)
File "cache.py", line 30, in make_cache_key
keyargs, keykwargs = self._memoize_kwargs_to_args(
File "init.py", line 651, in _memoize_kwargs_to_args
arg_default = get_arg_default(f, i)
File "flask_caching/utils.py", line 42, in get_arg_default
return arg_def if arg_def != inspect.Parameter.empty else None
File "pandas/core/generic.py", line 1439, in nonzero
raise ValueError(

Expected:

Cache the function correctly.

Environment:

• Python version: 3.9
• Flask-Caching version: 2.0.2

[Lxstr]

For anyone seeing this use args_to_ignore=["arg"] parameter.