def xml(self, operator='set', indent = ""):
        """Serialize the metadata field to XML"""
        xml = indent + "<meta id=\"" + self.key + "\""
        if operator != 'set':
            xml += " operator=\"" + operator + "\""
        if not self.value:
            xml += " />"
        else:
            xml += ">" + self.value + "</meta>"
        return xml
def xml ( self , operator = 'set' , indent = "" ) : xml = indent + "<meta id=\"" + self . key + "\"" if operator != 'set' : xml += " operator=\"" + operator + "\"" if not self . value : xml += " />" else : xml += ">" + self . value + "</meta>" return xml
Serialize the metadata field to XML