def msgstr
      begin
        if @scanner.scan(/msgstr/)
          skip_whitespace
          text = message_line
          add_result(:msgstr, text)
          message_multiline(:msgstr) if text.empty?
          skip_whitespace
          raise PoSyntaxError, "Unexpected content after expected message end #{@scanner.peek(10).inspect}" unless @scanner.eos?
        else
         raise PoSyntaxError, "Singular message without msgstr is not allowed. Line started unexpectedly with #{@scanner.peek(10).inspect}."
        end
      rescue PoSyntaxError => pe
        raise PoSyntaxError, "Syntax error in msgstr\n" + pe.message, pe.backtrace
      end
    end
def msgstr
      begin
        if @scanner.scan(/msgstr/)
          skip_whitespace
          text = message_line
          add_result(:msgstr, text)
          message_multiline(:msgstr) if text.empty?
          skip_whitespace
          raise PoSyntaxError, "Unexpected content after expected message end #{@scanner.peek(10).inspect}" unless @scanner.eos?
        else
         raise PoSyntaxError, "Singular message without msgstr is not allowed. Line started unexpectedly with #{@scanner.peek(10).inspect}."
        end
      rescue PoSyntaxError => pe
        raise PoSyntaxError, "Syntax error in msgstr\n" + pe.message, pe.backtrace
      end
    end
parses the msgstr singular line

 msgstr is required in singular translations