new_contents: """
  In DNA strings, symbols 'A' and 'T' are complements of each other, as are 'C' and 'G'.
  
  The reverse complement of a DNA string s is the string sc formed by reversing the symbols of s, then
  taking the complement of each symbol (e.g., the reverse complement of "GTCA" is "TGAC").
  
  Given: A DNA string s of length at most 1000 bp.
  
  Return: The reverse complement sc of s.
  """
  
  if __name__ == '__main__':
  
      inverse = {
          'A': 'T',
          'T': 'A',
          'C': 'G',
          'G': 'C',
          '\n': '',
      }
  
      with open('data/rosalind_revc.txt') as f:
          sequence = f.read()
  
      complement = ''
      for N in sequence:
          complement = inverse[N] + complement
  
      print complement
subject: Add solution to complementing a strand of DNA