def _create_extn_pattern(single_extn_symbols):
 return (((((((((((((_RFC3966_EXTN_PREFIX + _CAPTURING_EXTN_DIGITS) + u('|')) + u('[ \\u00A0\\t,]*(?:e?xt(?:ensi(?:o\\u0301?|\\u00F3))?n?|')) + u('\\uFF45?\\uFF58\\uFF54\\uFF4E?|')) + u('[')) + single_extn_symbols) + u(']|int|anexo|\\uFF49\\uFF4E\\uFF54)')) + u('[:\\.\\uFF0E]?[ \\u00A0\\t,-]*')) + _CAPTURING_EXTN_DIGITS) + u('#?|')) + u('[- ]+(')) + _DIGITS) + u('{1,5})#'))

def _create_extn_pattern ( single_extn_symbols ) : return ( ( ( ( ( ( ( ( ( ( ( ( ( _RFC3966_EXTN_PREFIX + _CAPTURING_EXTN_DIGITS ) + u ( '|' ) ) + u ( '[ \\u00A0\\t,]*(?:e?xt(?:ensi(?:o\\u0301?|\\u00F3))?n?|' ) ) + u ( '\\uFF45?\\uFF58\\uFF54\\uFF4E?|' ) ) + u ( '[' ) ) + single_extn_symbols ) + u ( ']|int|anexo|\\uFF49\\uFF4E\\uFF54)' ) ) + u ( '[:\\.\\uFF0E]?[ \\u00A0\\t,-]*' ) ) + _CAPTURING_EXTN_DIGITS ) + u ( '#?|' ) ) + u ( '[- ]+(' ) ) + _DIGITS ) + u ( '{1,5})#' ) )
helper initialiser method to create the regular-expression pattern to match extensions .