fix misplaced docstring

Author: yucongalicechen

src/diffpy/labpdfproc/tools.py

@@ -17,15 +17,15 @@ def set_output_directory(args):
     args argparse.Namespace
         the arguments from the parser
 
-    Returns
-    -------
-    pathlib.PosixPath that contains the full path of the output directory
-
     it is determined as follows:
     If user provides an output directory, use it.
     Otherwise, we set it to the current directory if nothing is provided.
     We then create the directory if it does not exist.
 
+    Returns
+    -------
+    pathlib.PosixPath that contains the full path of the output directory
+
     """
     output_dir = Path(args.output_directory).resolve() if args.output_directory else Path.cwd().resolve()
     output_dir.mkdir(parents=True, exist_ok=True)
@@ -110,13 +110,13 @@ def set_wavelength(args):
     args argparse.Namespace
         the arguments from the parser
 
+    we raise an ValueError if the input wavelength is non-positive
+    or if the input anode_type is not one of the known sources
+
     Returns
     -------
     args argparse.Namespace
 
-    we raise an ValueError if the input wavelength is non-positive
-    or if the input anode_type is not one of the known sources
-
     """
     if args.wavelength is not None and args.wavelength <= 0:
         raise ValueError(