old_contents: # Codon                 | Protein
  # :---                  | :---
  # AUG                   | Methionine
  # UUU, UUC              | Phenylalanine
  # UUA, UUG              | Leucine
  # UCU, UCC, UCA, UCG    | Serine
  # UAU, UAC              | Tyrosine
  # UGU, UGC              | Cysteine
  # UGG                   | Tryptophan
  # UAA, UAG, UGA         | STOP
  
  CODON_TO_PROTEIN = {
      "AUG": "Methionine",
      "UUU": "Phenylalanine",
      "UUC": "Phenylalanine",
      "UUA": "Leucine",
      "UUG": "Leucine",
      "UCU": "Serine",
      "UCC": "Serine",
      "UCA": "Serine",
      "UCG": "Serine",
      "UAU": "Tyrosine",
      "UAC": "Tyrosine",
      "UGU": "Cysteine",
      "UGC": "Cysteine",
      "UGG": "Tryptophan",
      "UAA": "STOP",
      "UAG": "STOP",
      "UGA": "STOP"
  }
  
  
  def proteins(strand):
      return [CODON_TO_PROTEIN[strand]]
  
new_contents: # Codon                 | Protein
  # :---                  | :---
  # AUG                   | Methionine
  # UUU, UUC              | Phenylalanine
  # UUA, UUG              | Leucine
  # UCU, UCC, UCA, UCG    | Serine
  # UAU, UAC              | Tyrosine
  # UGU, UGC              | Cysteine
  # UGG                   | Tryptophan
  # UAA, UAG, UGA         | STOP
  
  CODON_TO_PROTEIN = {
      "AUG": "Methionine",
      "UUU": "Phenylalanine",
      "UUC": "Phenylalanine",
      "UUA": "Leucine",
      "UUG": "Leucine",
      "UCU": "Serine",
      "UCC": "Serine",
      "UCA": "Serine",
      "UCG": "Serine",
      "UAU": "Tyrosine",
      "UAC": "Tyrosine",
      "UGU": "Cysteine",
      "UGC": "Cysteine",
      "UGG": "Tryptophan"
  }
  
  STOP_CODONS = set({"UAA", "UAG", "UGA"})
  
  
  def proteins(strand):
      if (strand in STOP_CODONS):
          return []
      return [CODON_TO_PROTEIN[strand]]
  
subject: Handle stop codons