human
Solve the following python programming problem given the following code:
def _test_kernel_param(self, kernel, psi2n = False) : 
    def f(p) : 
        kernel.param_array [:] = p 
        psi0 = kernel.psi0 (self.Z, self.qX) 
        psi1 = kernel.psi1 (self.Z, self.qX) 
        if (not psi2n) : 
            psi2 = kernel.psi2 (self.Z, self.qX) 
            return (((self.w1 * psi0).sum () + (self.w2 * psi1).sum ()) + (self.w3 * psi2).sum ()) 
else : 
            psi2 = kernel.psi2n (self.Z, self.qX) 
            return (((self.w1 * psi0).sum () + (self.w2 * psi1).sum ()) + (self.w3n * psi2).sum ()) 
def df(p) : 
        kernel.param_array [:] = p 
        kernel.update_gradients_expectations (self.w1, self.w2, (self.w3 if (not psi2n) else self.w3n), self.Z, self.qX) 
        return kernel.gradient.copy () 
from GPy.models import GradientChecker 
    m = GradientChecker (f, self, kernel.param_array.copy ()) 
    m.checkgrad (verbose = 1) 
    self.assertTrue (m.checkgrad ()) 

    
    

    Fix the buggy line: m = GradientChecker (f, self, kernel.param_array.copy ())
assistant
#Here is Python code to fix the buggy line: m = GradientChecker (f, self, kernel.

m = GradientChecker (f, def df(, kernel.param_array.copy ())