def SEIR(self, y, t, Beta, r, sigma):
  """
    The function that computes the diferential set of 
    equations of the SEIR Epidemic Model.
    
    :param tuple y: Tuple with the suceptible and infected data.
    :param array t: The time respective to each y set of samples.
    :param float Beta: The Beta parameter.
    :param float r: The r parameter.
    :param float sigma: The sigma parameter.
    
    :return: The derivative of the suceptible and infected data.
    :rtype: tuple
  """

  S, E, I, R = y
  Sdot = -Beta * S * I / self.N
  Edot = Beta * S * I / self.N - sigma * E
  Idot = sigma * E  - r * I
  Rdot = r * I
  return Sdot, Edot, Idot, Rdot