new_contents: """Leetcode 20. Valid Parentheses
  Easy
  
  URL: https://leetcode.com/problems/valid-parentheses/
  
  Given a string containing just the characters 
  '(', ')', '{', '}', '[' and ']', determine if the input string is valid.
  
  An input string is valid if:
  - Open brackets must be closed by the same type of brackets.
  - Open brackets must be closed in the correct order.
  
  Note that an empty string is also considered valid.
  
  Example 1:
  Input: "()"
  Output: true
  
  Example 2:
  Input: "()[]{}"
  Output: true
  
  Example 3:
  Input: "(]"
  Output: false
  
  Example 4:
  Input: "([)]"
  Output: false
  
  Example 5:
  Input: "{[]}"
  Output: true
  """
  
  class Solution(object):
      def isValid(self, s):
          """
          :type s: str
          :rtype: bool
          """
          pass
  
  
  def main():
  	pass
  
  
  if __name__ == '__main__':
  	main()
  
subject: Add lc020_valid_parentheses.py