Is replaceScipyNormPdf in MixtureEstimationMethods.py correct?

[ZhangBio]

At https://github.com/PacificBiosciences/kineticsTools/blob/master/kineticsTools/MixtureEstimationMethods.py#L86.

From the name of this function, it seems to be designed as a substitute of the scipy.stats.norm.pdf() and return the probablity of data under normal distribution (mu,1).
But it's easy to tell that the maximum value is not at "mu" (when mu is set), but is at "-inf".
Does this function perform what it's supposed to do? Or I misunderstood something?