email.utils.collapse_rfc2231_value()

email.utils.collapse_rfc2231_value(value, errors='replace', fallback_charset='us-ascii')

When a header parameter is encoded in RFC 2231 format, Message.get_param may return a 3-tuple containing the character set, language, and value. collapse_rfc2231_value() turns this into a unicode string. Optional errors is passed to the errors argument of str‘s encode() method; it defaults to 'replace'. Optional fallback_charset specifies the character set to use if the one in the RFC 2231 header is not known by Python; it defaults to 'us-ascii'.

For convenience, if the value passed to collapse_rfc2231_value() is not a tuple, it should be a string and it is returned unquoted.