def Hubble_convert(H_0):
    """
    Converts the Hubble parameter from km/s/Mpc to Myr^-1

    Parameters
    ----------
    H_0 : float
        The Hubble parameter in km/s/Mpc.

    Returns
    -------
    result : float
        The Hubble parameter in Myr^-1.

    """
    result = H_0*1000.0*3.1536*10**13/(3.09*10**16)/10**6 #This formula convert the Hubble parameter from
    #km/s/Mpc to Myr^-1 in order to match the unit convention in this program
    return result