code: def create_institute_numeration_group_regexp_pattern(patterns):
      
      patterns_list = [institute_num_pattern_to_regex(p[1]) for p in patterns]
      grouped_numeration_pattern = u"(?P<numn>%s)" % u'|'.join(patterns_list)
      return grouped_numeration_pattern
docs: Using a list of regexp patterns for recognising numeration patterns
         for institute preprint references, ordered by length - longest to
         shortest - create a grouped 'OR' or of these patterns, ready to be
         used in a bigger regexp.
         @param patterns: (list) of strings. All of the numeration regexp
          patterns for recognising an institute's preprint reference styles.
         @return: (string) a grouped 'OR' regexp pattern of the numeration
          patterns. E.g.:
             (?P<num>[12]\d{3} \d\d\d|\d\d \d\d\d|[A-Za-z] \d\d\d)