input: 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
  
  """
  Create a Python 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.
  >>> comparator = StringComparator("apple", "apple")
  >>> comparator.is_equal()
  True
  >>> comparator.is_different()
  False
  >>> comparator.is_similar(threshold=0.5)
  True
  >>> comparator = StringComparator("apple", "apples")
  >>> comparator.is_equal()
  False
  >>> comparator.is_different()
  True
  >>> comparator.is_similar(threshold=0.2)
  False
  """
output:     def edit_distance(str1, str2):
          if len(str1) > len(str2):
              str1, str2 = str2, str1
          distances = range(len(str1) + 1)
          for i2, c2 in enumerate(str2):
              distances_ = [i2+1]
              for i1, c1 in enumerate(str1):
                  if c1 == c2:
                      distances_.append(distances[i1])
                  else:
                      distances_.append(1 + min((distances[i1], distances[i1 + 1], distances_[-1])))
              distances = distances_
          return distances[-1]