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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def E_Advective_Dispersion(t, Pe):
 """Calculate a dimensionless measure of the output tracer concentration from a spike input to reactor with advection and dispersion. :param t: The time(s) at which to calculate the effluent concentration. Time can be made dimensionless by dividing by the residence time of the CMFR. :type t: float or numpy.array :param Pe: The ratio of advection to dispersion ((mean fluid velocity)/(Dispersion*flow path length)) :type Pe: float :return: dimensionless measure of the output tracer concentration (concentration * volume of reactor) / (mass of tracer) :rtype: float :Examples: 0.4774864 """

    # replace any times at zero with a number VERY close to zero to avoid
    # divide by zero errors
    if isinstance(t, list):
        t[t == 0] = 10**(-10)
    return (Pe/(4*np.pi*t))**(0.5)*np.exp((-Pe*((1-t)**2))/(4*t))