input: Write a function to implement the `StringComparator` class that receives two strings and has methods for comparing the strings and returning whether they are equal, different, or similar up to a provided threshold.
  
  class StringComparator:
  
      def __init__(self, string1, string2):
          self.string1 = string1
          self.string2 = string2
  
      def is_equal(self):
          return self.string1 == self.string2
  
      def is_different(self):
          return self.string1 != self.string2
  
      def is_similar(self, threshold=0.5):
          distance = edit_distance(self.string1, self.string2)
          max_length = max(len(self.string1), len(self.string2))
          return distance / max_length < threshold
  
  assert StringComparator("hello", "hello").is_equal() == True
  assert StringComparator("hello", "world").is_equal() == False
  assert StringComparator("hello", "world").is_different() == True
  assert StringComparator("hello", "hllo").is_similar(threshold=0.2) == True
  assert StringComparator("hello", "world").is_similar(threshold=0.2) == False
  assert StringComparator("hello", "hi").is_similar(threshold=0.8) == False
output: def __init__(self, string1, string2):
      self.string1 = string1
      self.string2 = string2
  
  def is_equal(self):
      return self.string1 == self.string2
  
  def is_different(self):
      return self.string1 != self.string2
  
  def is_similar(self, threshold=0.5):
      distance = edit_distance(self.string1, self.string2)
      max_length = max(len(self.string1), len(self.string2))
      return distance / max_length < threshold