gnu: Add python-expandvars.

* gnu/packages/python-xyz.scm (python-expandvars): New variable.

Change-Id: I2782f1bb09321944ddfe8f3957d8036c2988fabc

gnu/packages/python-xyz.scm

@@ -5421,6 +5421,29 @@ user configuration files.  It does not have support for serializing into YAML
 and is not compatible with JSON.")
     (license license:expat)))
 
+(define-public python-expandvars
+  (package
+    (name "python-expandvars")
+    (version "0.12.0")
+    (source
+     (origin
+       (method url-fetch)
+       (uri (pypi-uri "expandvars" version))
+       (sha256
+        (base32 "0i6q4i8dzsax85w1l2hc7saymyh3fw43vkifh5flpkr8ayjxy6kx"))))
+    (build-system pyproject-build-system)
+    (native-inputs
+     (list python-hatchling python-pytest python-pytest-cov))
+    (home-page "https://pypi.org/project/expandvars/")
+    (synopsis "Expand system variables Unix style")
+    (description "This module is inspired by GNU bash's variable expansion
+features.  It can be used as an alternative to Python's
+@code{os.path.expandvars} function.  A good use case is reading config files
+with the flexibility of reading values from environment variables using
+advanced features like returning a default value if some variable is not
+defined.")
+    (license license:expat)))
+
 (define-public python-extension-helpers
   (package
     (name "python-extension-helpers")