from typing import Callable


def is_such_at(func: Callable[[str], bool], index: int, text: str) -> bool:
	"""
	Whether a character at a string is of a certain class.
	:param func: a function
	:param index: a number indicating which character in the text
	:param text: a string
	:return: whether it is true
	"""
	return index < len(text) and func(text[index])