@classmethod
def poisson_one_more(cls, tau_1, tau_2, symbolic=False):
    """Asymptotic development of ``P(X_1 = X_2 + 1)``, where ``X_i ~ Poison(tau_i * n)``.

        Parameters
        ----------
        tau_1,tau_2 : Number
            The parameter of the Poisson distribution of ``X_i`` is ``tau_i * n``, where `n` tends to infinity.
        symbolic : bool
            Whether the computations are symbolic or numeric.

        Returns
        -------
        Asymptotic
            The asymptotic development of ``P(X_1 = X_2 + 1)``, where ``X_i ~ Poison(tau_i * n)``.

        Examples
        --------
            >>> from math import pi, log
            >>> print(Asymptotic.poisson_one_more(tau_1=0, tau_2=1/10))
            exp(- inf)
            >>> print(Asymptotic.poisson_one_more(tau_1=1/10, tau_2=0))
            exp(- 0.1 n + log n - 2.30259 + o(1))
        """
    return cls.poisson_x1_eq_x2_plus_k(tau_1, tau_2, 1, symbolic=symbolic)
