def bool_to_int(in_str):
    """
    It returns 1 if in_str is equal to t, 0 if in_str is equal to f else it returns empty.
    
    Input
        in_str - string, 

    Output
        1,0, , - int

    """

    if in_str == 't':
        return 1
    elif in_str == 'f':
        return 0
    else:
        return