Random Variables - Code error?

In Lecture 11, about Random Variables I'm confused with why at the end, the code for normal fitting is:

sample_distribution = ((1/np.sqrt(sample_std_dev * sample_std_dev * 2 * np.pi)) *
np.exp(-(x - sample_mean)*(x - sample_mean) / (2 * sample_std_dev * sample_std_dev)))


and in the exercises it's this code:

sample_distribution = ((1/(sample_std_dev * 2 * np.pi)) *
np.exp(-(x - sample_mean)*(x - sample_mean) / (2 * sample_std_dev * sample_std_dev)))


Shouldn't both be sample_std_dev*np.sqrt(2*np.pi) ?

It's probably my meager math and I'm just missing something very obvious... if that's the case can someone explain what we're trying to do here?