zinating
diff --git a/‎data_structures/hashing/double_hash.py‎
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@@ -1,4 +1,16 @@
 #!/usr/bin/env python3
+"""
+Double hashing is a collision resolving technique in Open Addressed Hash tables.
+Double hashing uses the idea of applying a second hash function to key when a collision
+occurs. The advantage of Double hashing is that it is one of the best form of  probing,
+producing a uniform distribution of records throughout a hash table. This technique
+does not yield any clusters. It is one of effective method for resolving collisions.
+
+Double hashing can be done using: (hash1(key) + i * hash2(key)) % TABLE_SIZE
+Where hash1() and hash2() are hash functions and TABLE_SIZE is size of hash table.
+
+Reference: https://en.wikipedia.org/wiki/Double_hashing
+"""
 from .hash_table import HashTable
 from .number_theory.prime_numbers import is_prime, next_prime