from asyncio import iscoroutinefunction
from inspect import signature
[docs]
def is_function(f: object, arg_count: int, coroutine: bool = False) -> bool:
"""
Check and require a function that can accept the specified number of
positional arguments, which either is or is not a coroutine
type casting "functions" are allowed, but only in the 1-argument form.
Args:
f: Function to check.
arg_count: Number of argument f should accept.
coroutine: Is a coroutine.
Return:
bool: is function and accepts the specified number of arguments.
"""
if not isinstance(arg_count, int) or arg_count < 0:
raise TypeError("arg_count must be a non-negative integer")
if not (callable(f) and bool(coroutine) is iscoroutinefunction(f)):
return False
if isinstance(f, type):
# for type casting functions, eg int, str, float
# only support the one-parameter form of these,
# otherwise the user should make an explicit function.
return arg_count == 1
try:
sig = signature(f)
except ValueError:
# some built-in functions/methods don't describe themselves to inspect
# we already know it's a callable and coroutine is correct.
return True
try:
inputs = [0] * arg_count
sig.bind(*inputs)
return True
except TypeError:
return False