code: def _parameter_constraints(self, theta_E, gamma, q, phi_G, s_scale):
          
          if theta_E < 0:
              theta_E = 0
          if s_scale < 0.00000001:
              s_scale = 0.00000001
          if gamma < 1.2:
              gamma = 1.2
              theta_E = 0
          if gamma > 2.9:
              gamma = 2.9
              theta_E = 0
          if q < 0.01:
              q = 0.01
              theta_E = 0
          if q > 1:
              q = 1.
              theta_E = 0
          return theta_E, gamma, q, phi_G, s_scale
docs: sets bounds to parameters due to numerical stability
          :param theta_E:
          :param gamma:
          :param q:
          :param phi_G:
          :param s_scale:
          :return: