def f(t):
 s1 = np.cos(((2 * np.pi) * t))
 e1 = np.exp((- t))
 return (s1 * e1)

def f ( t ) : s1 = np . cos ( ( ( 2 * np . pi ) * t ) ) e1 = np . exp ( ( - t ) ) return ( s1 * e1 )
very nice function .