diff --git a/src/caosadvancedtools/table_importer.py b/src/caosadvancedtools/table_importer.py
index 6fb4a28f17420df901ad33a2bbe57fbd63dfc190..0bc64d138ce4371f093ee0a98da2bfa937ca50b4 100755
--- a/src/caosadvancedtools/table_importer.py
+++ b/src/caosadvancedtools/table_importer.py
@@ -99,6 +99,8 @@ class XLS_Importer(object):
         converts an xls file into a Pandas DataFrame.
 
         The converters of the XLS_Importer object are used.
+
+        Raises: DataInconsistencyError
         """
         try:
             xls_file = pd.io.excel.ExcelFile(filename)
@@ -137,6 +139,8 @@ class XLS_Importer(object):
         """
         checks whether all required columns, i.e. columns for which converters
         were defined exist.
+
+        Raises: DataInconsistencyError
         """
 
         for col in self.required_columns: