The cmath.cosh() function returns the hyperbolic cosine of  the given complex number. The input value can be real or complex but the returned value will always be complex.

cmath.cosh(x)
x The angle in radians(real or complex) whose hyperbolic cosine we want.

 The function returns a complex number representing the hyperbolic cosine of the input radian angle.

import cmath 

print(cmath.cosh(-2.5))
print(cmath.cosh(0.36))
print(cmath.cosh(1 +2j ))
print(cmath.cosh(2+0.5j))