Exercise 4: Mapping a Triplet to a Codon Compose a function rna2codon which accepts a three-letter codon triplet and returns a string amino representing the corresponding amino acid per the table above. That is, the input 'GAU' should return 'D' . The function should convert any input into upper-case and should check that the codon is valid. If codon in invalid the function should return "Invalid" string. We provide a dictionary genetic_code which you may use in composing your function. #grade def rna2codon(triplet): genetic_code = { 'UU': 'F', 'UUC': 'F', 'UUA': 'l', 'UU': 'l', AUU': 'I', 'AUC': 'I', 'AUA': 'I', 'AUG': 'M', 'CUU': 'L', 'CC': 'L', 'CUA': 'L', 'CUG': 'L', 'GUU': 'V', 'GUC': 'V', 'GUA': 'V', 'GUG': 'V', 'UCU': 'S', 'UCC': 'S', 'UCA': 'S', 'UCG': 's', 'ACU': 'T', 'ACC': 'T', 'ACA': 'T', 'ACG': 'T', 'CCU': 'P', 'CCC': 'P', 'CCA': 'P', 'CCG': 'P', 'GCU': 'A', 'GCC': 'A', 'GCA': 'A', 'GCG': 'A', I* 'UAU': 'Y', 'UAC': 'Y', 'UAA': "UAG': 'AAU': 'N', 'AAC': 'N', 'AAA': 'K', 'AAG': 'K', 'CAU': 'H', 'CAC': 'H', 'CAA': 'Q', 'CAG': 'Q', 'GAU': 'D', 'GAC': 'D', 'GAA': 'E', 'GAG': 'E', 'CGU': 'R', 'CGC': 'R', 'CGA': 'R', 'CGG': 'R', 'GGU': 'G', 'GGC': 'G', 'GGA': 'G', 'GGG': 'G', 'UGU': 'C', 'UGC': 'C', 'UGA': '*', 'UGG': 'W', 'AGU': 'S', 'AGC': 'S', 'AGA': 'R', 'AGG': 'R', } allowed_codons = set('ACGU')