The RNA codon that codes for an amino acid
The corresponding amino acid or undefined if the RNA codon is invalid
//passing a valid RNA codon
getAminoAcidByCodon(new RNA('GCA')); //returns an AminoAcid object
//passing an invalid codon (wrong length)
getAminoAcidByCodon(new RNA('GC')); //returns undefined
Given a valid RNA codon, return the corresponding amino acid