Cannot be used on FIPS systems

[nutjob4life]

Using libgravatar on security-restricted systems (such as FIPS-enabled systems on newer U.S. Government computers) produces a stack trace. On such systems, the MD5 algorithm is disabled:

$ cat /etc/redhat-release
Red Hat Enterprise Linux release 8.7 (Ootpa)
$ fips-mode-setup --check
FIPS mode is enabled.
$ python3 -m venv venv
$ cd venv
$ . bin/activate
(venv) $ pip install libgravatar
Collecting libgravatar
  Downloading libgravatar-1.0.3-py2.py3-none-any.whl (17 kB)
Installing collected packages: libgravatar
Successfully installed libgravatar-1.0.3
$ python3
Python 3.9.12 (main, Mar  2 2023, 16:45:19) 
[GCC 8.5.0 20210514 (Red Hat 8.5.0-16.0.2)] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import libgravatar
>>> g = libgravatar.Gravatar('x@y.com')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/tmp/venv/lib/python3.9/site-packages/libgravatar/__init__.py", line 67, in __init__
    self.email_hash = md5_hash(self.email)
  File "/tmp/venv/lib/python3.9/site-packages/libgravatar/__init__.py", line 252, in md5_hash
    return md5(string.encode("utf-8")).hexdigest()
ValueError: [digital envelope routines: EVP_DigestInit_ex] disabled for FIPS

On Python 3.9+, it's possible to pass a usedforsecurity=False flag to hashlib.md5 to indicate that MD5 is not being used for security but for harmless fingerprinting purposes.