code: def _verify_credentials(self):
          
          r = requests.get(self.apiurl + "account/verify_credentials.xml",
                           auth=HTTPBasicAuth(self._username, self._password),
                           headers=self.header)
          if r.status_code != 200:
              raise UserLoginFailed("Username or Password incorrect.")
docs: An internal method that verifies the credentials given at instantiation.
  
          :raises: :class:`Pymoe.errors.UserLoginFailed`