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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_user(self, userPk):
 """Returns the user specified with the user's Pk or UUID"""

        r = self._request('user/' + str(userPk))
        if r:
            # Set base properties and copy data inside the user
            u = User()
            u.pk = u.id = userPk
            u.__dict__.update(r.json())
            return u
        return None