docs: 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