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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 elliot_function( signal, derivative=False ):
 """ A fast approximation of sigmoid """

    s = 1 # steepness
    
    abs_signal = (1 + np.abs(signal * s))
    if derivative:
        return 0.5 * s / abs_signal**2
    else:
        # Return the activation signal
        return 0.5*(signal * s) / abs_signal + 0.5