Add a Field Write to this class

        :param method:
        :param classobj:
        :param field:
        :return:

def AddFXrefWrite(self, method, classobj, field):
        """
        Add a Field Write to this class

        :param method:
        :param classobj:
        :param field:
        :return:
        """
        if field not in self._fields:
            self._fields[field] = FieldClassAnalysis(field)
        self._fields[field].AddXrefWrite(classobj, method)