diff --git a/ohmpi/hardware_system.py b/ohmpi/hardware_system.py
index 094023a9332cdf7cf38514f04b990e6ca89df86d..2f4d596c3027c0e2822d0aae5eb652454d108797 100644
--- a/ohmpi/hardware_system.py
+++ b/ohmpi/hardware_system.py
@@ -57,6 +57,8 @@ def elapsed_seconds(start_time):
 
 
 class OhmPiHardware:
+    """OhmPiHardware class.
+        """
     def __init__(self, **kwargs):
         # OhmPiHardware initialization
         self.exec_logger = kwargs.pop('exec_logger', create_stdout_logger('exec_hw'))