new_contents: '''
  Written by Cham K.
  June 16th 2015
  '''
  
  from sequence_manipulation import nucleotide_count
  
  def GC_content(sequence, percent=True):
      ''' (str, bool) -> (float)
      Returns the GC-content as a non-rounded percentage (or ratio if percent=False) of a DNA sequence.
      Can process upper-case and lower-case sequence input with or without whitespace characters.
      >>> GC_content('G A T A C C')
      50.0
      >>> GC_content('G A A A T C A C C')
      44.44444444444444
      >>> GC_content('G A A A T C A C C', False)
      0.4444444444444444
      '''
      module = nucleotide_count
      A = module.nucleotide_count(sequence, 'A')
      T = module.nucleotide_count(sequence, 'T')
      C = module.nucleotide_count(sequence, 'C')
      G = module.nucleotide_count(sequence, 'G')
      if percent == True: return (G+C)/(A+T+C+G)*100
      elif percent == False: return (G+C)/(A+T+C+G)
  
subject: Create GC_content.py