**access_token**

        Returns a valid access token.  If the user is not currently logged in, attempts to do so.
        If the current time exceeds the grace period, attempts to retrieve a new access token.

        Input:
            * None

        Output:
            * A valid access token

        Example::

            print "Your access token is currently %s" % client.user.access_token()

def access_token(self):
        """
        **access_token**

        Returns a valid access token.  If the user is not currently logged in, attempts to do so.
        If the current time exceeds the grace period, attempts to retrieve a new access token.

        Input:
            * None

        Output:
            * A valid access token

        Example::

            print "Your access token is currently %s" % client.user.access_token()
        """
        if not self._access_token:
            self.login()

        if time() > (self.access_token_expires - self.access_token_grace):
            self.login({"refreshtoken": self.refresh_token})

        return self._access_token