new_contents: import numpy as _np
  import pyaccel as _pa
  import pymodels as _pm
  
  
  class EmittanceExchangeSimul:
  
      def __init__(self, accelerator='bo'):
  
          ACC_LIST = ['bo', ]
  
          self._model = None
  
          if accelerator not in ACC_LIST:
              raise NotImplementedError(
                  'Simulation not implemented for the passed accelerator')
  
          self._model = _pm.bo.create_accelerator(energy=3e9)
  
      @property
      def model(self):
          return self._model
  
      @staticmethod
      def calc_emit_exchange_quality(self, emit1_0, emit2_0, emit1):
          """."""
          r = 1 - (emit1 - emit2_0)/(emit1_0 - emit2_0)
          return r
  
      @staticmethod
      def C_to_KsL(self, C):
          fam_data = _pm.bo.get_family_data(self.model)
          qs_idx = fam_data['QS']['index']
          ed_tang, *_ = _pa.optics.calc_edwards_teng(accelerator=self.model)
          beta1 = ed_tang.beta1[qs_idx[0]]
          beta2 = ed_tang.beta2[qs_idx[0]]
          KsL = -2 * _np.pi * C / _np.sqrt(beta1 * beta2)
  
          return KsL[0]
  
      @staticmethod
      def KsL_to_C(self, KsL):
          fam_data = _pm.bo.get_family_data(self.model)
          qs_idx = fam_data['QS']['index']
          ed_tang, *_ = _pa.optics.calc_edwards_teng(accelerator=self.model)
          beta1 = ed_tang.beta1[qs_idx[0][0]]
          beta2 = ed_tang.beta2[qs_idx[0][0]]
          C = _np.abs(KsL * _np.sqrt(beta1 * beta2)/(2 * _np.pi))
  
          return C
  
subject: Create a class to simulate the emittance exchange dynamical process.