input: Write a function to implement a Python class called `StringComparator` 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
  
  # Testing the class
  comparator1 = StringComparator("hello", "hello")
  assert comparator1.is_equal() == True
  assert comparator1.is_different() == False
  assert comparator1.is_similar() == True
  
  comparator2 = StringComparator("hello", "hella")
  assert comparator2.is_equal() == False
  assert comparator2.is_different() == True
  assert comparator2.is_similar(threshold=0.2) == False
  assert comparator2.is_similar(threshold=0.4) == True
  
  comparator3 = StringComparator("hello", "world")
  assert comparator3.is_equal() == False
  assert comparator3.is_different() == True
  assert comparator3.is_similar() == False
  
output: 
  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
  