def METHOD_NAME(method='GET', canonical_uri='/', params={}, headers={}):
    access_key = Credentials.access_key
    secret_key = Credentials.secret_key
    str_to_sign = _create_str_to_sign(method, canonical_uri, params, headers)
    signature = utf8_decode(base64.encodestring(
        hmac.new(utf8_encode(secret_key), str_to_sign, sha1).digest()).strip())
    auth_header = "AWS %s:%s" % (access_key, signature)
    return auth_header