Formats a phone number for out-of-country dialing purposes.

    Note that in this version, if the number was entered originally using
    alpha characters and this version of the number is stored in raw_input,
    this representation of the number will be used rather than the digit
    representation. Grouping information, as specified by characters such as
    "-" and " ", will be retained.

    Caveats:

     - This will not produce good results if the country calling code is both
       present in the raw input _and_ is the start of the national
       number. This is not a problem in the regions which typically use alpha
       numbers.

     - This will also not produce good results if the raw input has any
       grouping information within the first three digits of the national
       number, and if the function needs to strip preceding digits/words in
       the raw input before these digits. Normally people group the first
       three digits together so this is not a huge problem - and will be fixed
       if it proves to be so.

    Arguments:
    numobj -- The phone number that needs to be formatted.
    region_calling_from -- The region where the call is being placed.

    Returns the formatted phone number

def format_out_of_country_keeping_alpha_chars(numobj, region_calling_from):
    """Formats a phone number for out-of-country dialing purposes.

    Note that in this version, if the number was entered originally using
    alpha characters and this version of the number is stored in raw_input,
    this representation of the number will be used rather than the digit
    representation. Grouping information, as specified by characters such as
    "-" and " ", will be retained.

    Caveats:

     - This will not produce good results if the country calling code is both
       present in the raw input _and_ is the start of the national
       number. This is not a problem in the regions which typically use alpha
       numbers.

     - This will also not produce good results if the raw input has any
       grouping information within the first three digits of the national
       number, and if the function needs to strip preceding digits/words in
       the raw input before these digits. Normally people group the first
       three digits together so this is not a huge problem - and will be fixed
       if it proves to be so.

    Arguments:
    numobj -- The phone number that needs to be formatted.
    region_calling_from -- The region where the call is being placed.

    Returns the formatted phone number
    """
    num_raw_input = numobj.raw_input
    # If there is no raw input, then we can't keep alpha characters because there aren't any.
    # In this case, we return format_out_of_country_calling_number.
    if num_raw_input is None or len(num_raw_input) == 0:
        return format_out_of_country_calling_number(numobj, region_calling_from)
    country_code = numobj.country_code
    if not _has_valid_country_calling_code(country_code):
        return num_raw_input
    # Strip any prefix such as country calling code, IDD, that was present. We
    # do this by comparing the number in raw_input with the parsed number.  To
    # do this, first we normalize punctuation. We retain number grouping
    # symbols such as " " only.
    num_raw_input = _normalize_helper(num_raw_input,
                                      _ALL_PLUS_NUMBER_GROUPING_SYMBOLS,
                                      True)
    # Now we trim everything before the first three digits in the parsed
    # number. We choose three because all valid alpha numbers have 3 digits at
    # the start - if it does not, then we don't trim anything at
    # all. Similarly, if the national number was less than three digits, we
    # don't trim anything at all.
    national_number = national_significant_number(numobj)
    if len(national_number) > 3:
        first_national_number_digit = num_raw_input.find(national_number[:3])
        if first_national_number_digit != -1:
            num_raw_input = num_raw_input[first_national_number_digit:]

    metadata_for_region_calling_from = PhoneMetadata.metadata_for_region(region_calling_from.upper(), None)
    if country_code == _NANPA_COUNTRY_CODE:
        if is_nanpa_country(region_calling_from):
            return unicod(country_code) + U_SPACE + num_raw_input
    elif (metadata_for_region_calling_from is not None and
          country_code == country_code_for_region(region_calling_from)):
        formatting_pattern = _choose_formatting_pattern_for_number(metadata_for_region_calling_from.number_format,
                                                                   national_number)
        if formatting_pattern is None:
            # If no pattern above is matched, we format the original input
            return num_raw_input
        new_format = _copy_number_format(formatting_pattern)
        # The first group is the first group of digits that the user
        # wrote together.
        new_format.pattern = u("(\\d+)(.*)")
        # Here we just concatenate them back together after the national
        # prefix has been fixed.
        new_format.format = u(r"\1\2")
        # Now we format using this pattern instead of the default pattern,
        # but with the national prefix prefixed if necessary.
        # This will not work in the cases where the pattern (and not the
        # leading digits) decide whether a national prefix needs to be used,
        # since we have overridden the pattern to match anything, but that is
        # not the case in the metadata to date.
        return _format_nsn_using_pattern(num_raw_input,
                                         new_format,
                                         PhoneNumberFormat.NATIONAL)
    i18n_prefix_for_formatting = U_EMPTY_STRING
    # If an unsupported region-calling-from is entered, or a country with
    # multiple international prefixes, the international format of the number
    # is returned, unless there is a preferred international prefix.
    if metadata_for_region_calling_from is not None:
        international_prefix = metadata_for_region_calling_from.international_prefix
        i18n_match = fullmatch(_SINGLE_INTERNATIONAL_PREFIX, international_prefix)
        if i18n_match:
            i18n_prefix_for_formatting = international_prefix
        else:
            i18n_prefix_for_formatting = metadata_for_region_calling_from.preferred_international_prefix

    region_code = region_code_for_country_code(country_code)
    # Metadata cannot be None because the country calling code is valid.
    metadata_for_region = PhoneMetadata.metadata_for_region_or_calling_code(country_code, region_code)
    formatted_number = _maybe_append_formatted_extension(numobj,
                                                         metadata_for_region,
                                                         PhoneNumberFormat.INTERNATIONAL,
                                                         num_raw_input)
    if i18n_prefix_for_formatting:
        formatted_number = (i18n_prefix_for_formatting + U_SPACE +
                            unicod(country_code) + U_SPACE + formatted_number)
    else:
        # Invalid region entered as country-calling-from (so no metadata was
        # found for it) or the region chosen has multiple international
        # dialling prefixes.
        formatted_number = _prefix_number_with_country_calling_code(country_code,
                                                                    PhoneNumberFormat.INTERNATIONAL,
                                                                    formatted_number)
    return formatted_number