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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 access_token(self):
 """return an Oauth 2.0 Bearer access token if it can be found"""

        access_token = self.get_auth_bearer()
        if not access_token:
            access_token = self.query_kwargs.get('access_token', '')
            if not access_token:
                access_token = self.body_kwargs.get('access_token', '')

        return access_token