human
Solve the following python programming problem given the following code:
@ defun 
def _lower_gamma(ctx, z, b, regularized = False) : 
    if ctx.isnpint (z) : 
        return type (z) (ctx.inf) 
G = ([z] * regularized) 
    negb = ctx.fneg (ctx, exact = True) 
    def h(z) : 
        T1 = ([ctx.exp (negb), b, z], [1, z, (- 1)], [], G, [1], [(1 + z)], b) 
        return (T1,) 
return ctx.hypercomb (h, [z]) 

    
    

    Fix the buggy line: negb = ctx.fneg (ctx, exact = True)
assistant
#Here is Python program to fix the buggy line: negb = ctx.

negb = ctx.fneg (b, exact = True)