Return the blood alcohol content (per mill) for a person with the
     given body stats and amount of alcohol (in gramm) in blood

def gramm_to_promille(gramm, age, weight, height, sex):
  """Return the blood alcohol content (per mill) for a person with the
     given body stats and amount of alcohol (in gramm) in blood
  """
  bw = calculate_bw(age, weight, height, sex)
  return (gramm * W) / (PB * bw)