text: def max_and_min(point):
      margin = abs(point * 0.05)
      max = point + margin
      min = point - margin
      return (max, min)
  
  
  def boiling_material(boiling_map, boiling_point):
      for key in boiling_map:
          max, min = max_and_min(boiling_map[key])
          if (min <= boiling_point <= max):
              return key
      return 'Unknown'
  
  
  def seed():
      return {
          'Butane': -0.5,
          'Cooper': 1187,
          'Gold': 2660,
          'Mercury': 357,
          'Methane': -161.7,
          'Nonane': 150.8,
          'Silver': 2197,
          'Walter': 100
      }
    
  print(boiling_material(seed(), -0.475))
  