input: from typing import Callable
  
  def sum_using_lambda(a: int, b: int) -> Callable[[int, int], int]:
      """ Create a lambda function that calculates the sum of two integers and return it.
      >>> sum_using_lambda = sum_using_lambda(3, 4)
      >>> sum_using_lambda(3, 4)
      7
      """
      return lambda a, b: a + b
output:     return lambda a, b: a + b