[SciPy-User] Which stats package am I missing for a function to do L-moments to Pearson 3 parameters calculation?

[James Adams]

I'm writing a Python program which needs to compute Pearson Type III
parameters from L-moments, and then calculate the cumulative
distribution function (CDF) using those parameters.

For going from L-moments to Pearson parameters I've found a function
in the source for hydroclimpy (the _lmparams_pearson3 function in
trunk/hydroclimpy/scikits/hydroclimpy/stats/lmoments.py) which might
do the trick, although it uses L-statistics rather than L-moments as
its input, but I assume that that is an easy conversion.  Is this a
good approach, or is there a better/more standard way of doing this?

The next step is to find a function that calculates the CDF for a
Pearson Type III distribution.  It looks like I'll need to make sure
that I have a Pearson Type III continuous distribution installed, is
this correct?  If so then where can I find these distribution classes
for installation, and/or how can I confirm that these are properly
installed?

Thanks in advance for any suggestions or comments.  I'm a new Python
programmer and new to doing this kind of math; my apologies if this is
too much of an open-ended/beginner's question.

--James