Catmandu::Fix::Condition::is_valid_issn - condition on validity of issn numbers

       Catmandu::Fix::Condition::is_valid_issn - condition on validity of issn numbers

       Catmandu::Fix

perl v5.36.0                                       2023-02-09              Catmandu::Fix:...::is_valid_issn(3pm)

          if is_valid_issn(issn_field)
            ...
          else
            ...
          end