input: def element_exists(elem, list_int):
      """ Checks if a given element exists within a given list of integers.
      >>> element_exists(5, [1, 2, 3, 4, 5])
      True
      >>> element_exists(10, [1, 2, 3, 4, 5])
      False
      """
      return elem in list_int
output:     return elem in list_int