DOC: Add docstring to MultiIndex._lexsort_depth

Author: nrebena

pandas/core/indexes/multi.py

@@ -1797,6 +1797,14 @@ def lexsort_depth(self):
         return self._lexsort_depth()
 
     def _lexsort_depth(self):
+        """
+        Compute and return the lexsort_depth, the number of levels of the
+        MultiIndex that are sorted lexically
+
+        Returns
+        ------
+        int
+        """
         int64_codes = [ensure_int64(level_codes) for level_codes in self.codes]
         for k in range(self.nlevels, 0, -1):
             if libalgos.is_lexsorted(int64_codes[:k]):