Add documentation links for platformdirs package and update data load…

…ing module

docs/source/conf.py

@@ -73,6 +73,7 @@
     "scipy": ("https://docs.scipy.org/doc/scipy/reference/", None),
     "numpy": ("https://numpy.org/doc/stable/", None),
     "git": ("https://gitpython.readthedocs.io/en/stable/", None),
+    "platformdirs": ("https://platformdirs.readthedocs.io/en/latest/", None),
 }
 
 # html_logo = "imgs/xxx.png"

mltb2/data.py

@@ -4,7 +4,17 @@
 # This software is distributed under the terms of the MIT license
 # which is available at https://opensource.org/licenses/MIT
 
-"""Data loading module.
+"""This module offers tools for loading data.
+
+The following tabular data sets are supported:
+
+- colon: `<http://genomics-pubs.princeton.edu/oncology/affydata/index.html>`_
+- prostate: `<https://web.stanford.edu/~hastie/CASI_files/DATA/prostate.html>`_
+- leukemia_big: `<https://web.stanford.edu/~hastie/CASI_files/DATA/leukemia.html>`_
+
+After loading the data from the internet it is parsed, converted and
+cached in the mltb2 data directory.
+This data directory is determined by :func:`mltb2.files.get_and_create_mltb2_data_dir`.
 
 Hint:
     Use pip to install the necessary dependencies for this module:

mltb2/files.py

@@ -19,11 +19,15 @@
 
 
 def get_and_create_mltb2_data_dir(mltb2_base_data_dir: Optional[str] = None) -> str:
-    """Return and create mltb data dir.
+    """Return and create a data dir for mltb2.
+
+    The exact directory is given by the ``mltb2_base_data_dir`` as the base folder
+    and then the folder ``mltb2`` is appended.
 
     Args:
         mltb2_base_data_dir: The base data directory. If ``None`` the default
-            user data directory is used.
+            user data directory is used. The default user data directory is
+            determined by :func:`platformdirs.user_data_dir`.
 
     Returns:
         The directory path.