dash/underscore on name of package uploaded on pypi

[ast]

Hello

I just uploaded a package on pypi, whose name is "arith_lib"

The strange thing is that on pypi the package is renamed "arith-lib"
The underscore is substitued with a dash

If we search for this package:

pip search arith

arith-lib (2.0.0) - A set of functions for miscellaneous arithmetic
(so a dash)

For installation both:

pip install -U arith_lib
pip install -U arith-lib

are working well

and in both case I got a directory with an underscore

C:\Program Files\Python36-32\Lib\site-packages

28/02/2019  16:57    <REP>          arith_lib
28/02/2019  16:57    <REP>          arith_lib-2.0.0.dist-info

What happens ?