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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def start_tag(self, alt=None, empty=False):
 """Return XML start tag for the receiver."""

        if alt:
            name = alt
        else:
            name = self.name
        result = "<" + name
        for it in self.attr:
            result += ' %s="%s"' % (it, escape(self.attr[it], {'"':"&quot;", '%': "%%"}))
        if empty:
            return result + "/>%s"
        else:
            return result + ">"