DOC: Fix validation error RT01 in pandas/io (pandas-dev#25356)

Author: ihsansecer

pandas/io/pytables.py

@@ -535,6 +535,10 @@ def keys(self):
         Return a (potentially unordered) list of the keys corresponding to the
         objects stored in the HDFStore. These are ABSOLUTE path-names (e.g.
         have the leading '/'
+
+        Returns
+        -------
+        list
         """
         return [n._v_pathname for n in self.groups()]
 
@@ -1080,6 +1084,10 @@ def create_table_index(self, key, **kwargs):
     def groups(self):
         """return a list of all the top-level nodes (that are not themselves a
         pandas storage object)
+
+        Returns
+        -------
+        list
         """
         _tables()
         self._check_if_open()
@@ -1214,6 +1222,10 @@ def info(self):
         Print detailed information on the store.
 
         .. versionadded:: 0.21.0
+
+        Returns
+        -------
+        str
         """
         output = '{type}\nFile path: {path}\n'.format(
             type=type(self), path=pprint_thing(self._path))

pandas/io/stata.py

@@ -1750,13 +1750,21 @@ def variable_labels(self):
         """
         Return variable labels as a dict, associating each variable name
         with corresponding label.
+
+        Returns
+        -------
+        dict
         """
         return dict(zip(self.varlist, self._variable_labels))
 
     def value_labels(self):
         """
         Return a dict, associating each variable name a dict, associating
         each value its corresponding label.
+
+        Returns
+        -------
+        dict
         """
         if not self._value_labels_read:
             self._read_value_labels()