input: Write a python function to modify the case of strings using a class with methods to convert to upper case, lower case, and title case.
  assert StringCaseModifier('Hello World').to_upper() == 'HELLO WORLD'
  assert StringCaseModifier('Hello World').to_lower() == 'hello world'
  assert StringCaseModifier('hello world').to_title() == 'Hello World'
output: class StringCaseModifier:
      def __init__(self, text):
          self.text = text
  
      def to_upper(self):
          return self.text.upper()
  
      def to_lower(self):
          return self.text.lower()
  
      def to_title(self):
          return self.text.title()