all Python 3inspectfunction

inspect.isclass()

object kind checks

Checks that an object is a class, built-in or user-defined; an instance of a class is not a class.

Syntax

inspect.isclass(object) -> bool

A parameterized generic such as list[int] is not a class: isclass gives False even though list[int]() builds a list, because it is a types.GenericAlias. The function is equivalent to isinstance(obj, type), so a class with a metaclass passes too. Before asking 'is it a subclass' you need this check: issubclass(3, int) fails with TypeError.

Examples

import inspect
class A: pass
print(inspect.isclass(A), inspect.isclass(A()))  # → True False
print(inspect.isclass(int), inspect.isclass(list[int]))  # → True False
issubclass(3, int)  # → TypeError: issubclass() arg 1 must be a class

See also

Common errors

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