import re


def strip_down_to_AZ(string_to_strip):
    """Makes a string to uppercase and strips the string of non-alphabet characters"""
    # only allow A-Z characters
    pattern = "[A-Z]"
    # cast all letters to uppercase.
    string_to_strip = str(string_to_strip).upper()
    # return all letters found.
    return "".join(re.findall(pattern, string_to_strip))