diff --git a/README.rst b/README.rst
index 69c92f8..b1d533a 100644
--- a/README.rst
+++ b/README.rst
@@ -30,6 +30,7 @@ Installation
 
 Choose one from the following.
 
+- Install with pip :code:`pip install apyori`.
 - Put *apyori.py* into your project.
 - Run :code:`python setup.py install`.
 
diff --git a/apyori.py b/apyori.py
index b618e63..5471bf7 100755
--- a/apyori.py
+++ b/apyori.py
@@ -260,6 +260,9 @@ def apriori(transactions, **kwargs):
         max_length -- The maximum length of the relation (integer).
     """
     # Parse the arguments.
+    for k in kwargs.keys():
+        assert k in ['min_support', 'min_confidence', 'min_lift', 'max_length', '_gen_support_records',
+                     '_gen_ordered_statistics', '_filter_ordered_statistics'], "%s is not a valid key" % k
     min_support = kwargs.get('min_support', 0.1)
     min_confidence = kwargs.get('min_confidence', 0.0)
     min_lift = kwargs.get('min_lift', 0.0)