    # File lib/gettext/tools/pomessage.rb, line 69
        def merge(other)
          return self unless other
          raise ParseError, "Translation targets do not match: \n" \
          "  self: #{self.inspect}\n  other: '#{other.inspect}'" unless self == other
          if other.msgid_plural && !self.msgid_plural
            res = other
            unless (res.sources.include? self.sources[0])
              res.sources += self.sources
              res.add_comment(self.comment)
            end
          else
            res = self
            unless (res.sources.include? other.sources[0])
              res.sources += other.sources
              res.add_comment(other.comment)
            end
          end
          res
        end