input: def element_exists(elem, list_int):
    """ Check if an element exists within a given list of integers.
    >>> element_exists(3, [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