old_contents: def to_rna(text):
    complement = ''
    char_complement = ''
    for char in text:
      char_complement = transcript(char)
      if char_complement is '':
        return ''
      complement += char_complement
  
    return complement
  
  def transcript(char):
    alphabet = {'G' : 'C', 'C' : 'G', 'T' : 'A', 'A' : 'U'}
    if char not in alphabet:
      return ''
  
    return alphabet[char]
  
new_contents: def to_rna(text):
    complement = ''
    alphabet = {'G' : 'C', 'C' : 'G', 'T' : 'A', 'A' : 'U'}
  
    for char in text:
      if char not in alphabet:
        return ''
      complement += alphabet[char]
  
    return complement
  
subject: make rna simple