code: def transSect(theta=None, rho=None, gamma=None):
      
      m = np.eye(6, 6, dtype=np.float64)
      if None in (theta, rho, gamma):
          print("warning: 'theta', 'rho', 'gamma' should be positive float numbers.")
          return m
      else:
          rc = rho * np.cos(theta)
          rs = rho * np.sin(theta)
          m[0, 0] = m[1, 1] = rc / rho
          m[0, 1] = rs
          m[0, 5] = rho - rc
          m[1, 0] = -np.sin(theta) / rho
          m[1, 5] = rs / rho
          m[2, 3] = rho * np.sin(theta)
          m[4, 0] = m[1, 5]
          m[4, 1] = m[0, 5]
          m[4, 5] = rho * np.sin(theta) / gamma / gamma - rho * theta + rs
          return m
docs: Transport matrix of sector dipole
  
      :param theta: bending angle in [RAD]
      :param rho: bending radius in [m]
      :param gamma: electron energy, gamma value
      :return: 6x6 numpy array