diff --git a/pygromacs/gmxfiles.py b/pygromacs/gmxfiles.py
index a3a3ff2..d402d6c 100644
--- a/pygromacs/gmxfiles.py
+++ b/pygromacs/gmxfiles.py
@@ -2,9 +2,10 @@
 
 import os
 from contextlib import redirect_stdout
-
 from pygromacs.utils import verify_path
 
+"""Interfaces for reading and modifying Gromacs standard files."""
+
 class Topol(object):
 
     def __init__(self, **kwargs):