If you use the same key twice in a hash, you will end up overwriting the original value.
Consider this example:
h2['Product1'] = 'A' h2['Product2'] = 'B' h2['Product3'] = 'C' h2['Product1'] = 'D'
Here the key 'Product1' has been used twice.
As a consequence, the original value, 'A', has been replaced by 'D', resulting in this hash: