def METHOD_NAME(x, a, b, c):
    """
    Gompertz growth function.
    sigmoidal family
    a is the upper asymptote, since
    b, c are negative numbers
    b sets the displacement along the x axis (translates the graph to the left or right)
    c sets the growth rate (y scaling)
    e.g. used to model the growth of tumors
    http://en.wikipedia.org/wiki/Gompertz_function
    """
    return a * np.exp(-b * np.exp(-c * x))
    # return a + b * np.exp(np.exp(-k*(x-i)))