def add(self, key, value):
index = self._get_hash_key(key)
if (self._hash_table[index]):
# Need to check for duplicate keys
# Overwrite value for existing key
self._hash_table[index].add_rear(key, value)
else:
hash_bucket = SingleLinkedList()
hash_bucket.add_rear(key, value)
self._hash_table[index] = hash_bucket
