[6] pry(#<HashTable>)> arr = Array.new(10,[])
=> [[], [], [], [], [], [], [], [], [], []]
[7] pry(#<HashTable>)> arr[2].unshift(3)
=> [3]
[8] pry(#<HashTable>)> arr
=> [[3], [3], [3], [3], [3], [3], [3], [3], [3], [3]]