<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _get_params(self):
 """return the value of the parameters."""

        return np.hstack((self.varianceU,self.varianceY, self.lengthscaleU,self.lengthscaleY))