<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def change_number_matches(self, current_match=0, total_matches=0):

 """Change number of match and total matches."""

        if current_match and total_matches:
            matches_string = u"{} {} {}".format(current_match, _(u"of"),
                                               total_matches)
            self.number_matches_text.setText(matches_string)
        elif total_matches:
            matches_string = u"{} {}".format(total_matches, _(u"matches"))
            self.number_matches_text.setText(matches_string)
        else:
            self.number_matches_text.setText(_(u"no matches"))