The mutation reader

You will write three small functions that read an mRNA and judge a mutation. The genetic code is already in the program as the table TABLE. A stop codon is written as *.

The idea. Read the codons in groups of three. A silent change keeps the amino acid. A nonsense change makes a stop codon. A shift of the frame happens when the number of bases inserted or deleted is not a multiple of 3.

Your tasks.

1. Finish translate. It gives the amino acids of an mRNA as a string of letters, and it stops at the first stop codon.
2. Finish classify. It gives "silent", "missense" or "nonsense" for a codon that changes into another.
3. Finish frame_kept. It says whether inserting (positive) or deleting (negative) a number of bases keeps the reading frame.