docs: def _parse_summaryRecordSysNumber(summaryRecordSysNumber):
      """
      Try to parse vague, not likely machine-readable description and return
      first token, which contains enough numbers in it.
      """
      def number_of_digits(token):
          digits = filter(lambda x: x.isdigit(), token)
          return len(digits)
  
      tokens = map(
          lambda x: remove_hairs(x, r" .,:;<>(){}[]\/"),
          summaryRecordSysNumber.split()
      )
  
      # pick only tokens that contains 3 digits
      contains_digits = filter(lambda x: number_of_digits(x) > 3, tokens)
  
      if not contains_digits:
          return ""
  
      return contains_digits[0]