@isqua: Please include the following test where unique string is at the start of the array as in my case as if somebody uses reference string from array to compare the strings.
Most of the time people use 0th index as reference.

Test:
['foo', 'abc', 'acb', 'bac', 'bca', 'cab', 'cba' ]

As given in the instructions please filter out special chars(@#$% etc.) and numbers(0-9) from input and dictionary then use it for further operation.

I'm stuck with the last test while submitting .. Don't forget those special characters!: [] should equal ['Nopesville']
How can I fix this ? Since the author hasn't mentioned this in the description.