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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 get_userplaycount(self):
 """Returns the number of plays by a given username"""


        if not self.username:
            return

        params = self._get_params()
        params["username"] = self.username

        doc = self._request(self.ws_prefix + ".getInfo", True, params)
        return _number(_extract(doc, "userplaycount"))