new_contents: """ Valid Number
  A valid number can be split up into these components (in order):
  
      1. A decimal number or an integer.
      2. (Optional) An 'e' or 'E', followed by an integer.
  
  A decimal number can be split up into these components (in order):
  
      1. (Optional) A sign character (either '+' or '-' ).
      2. One of the following formats:
          1. At least one digit followed by a dot '.'.
          2. At least one digit, followed by a dot '.', followed by at least one digit.
          3. A dot '.', followed by at least one digit.
  
  An integer can be split up into these components (in order):
  
      1. (Optional) A sign chracter (either '+' or '-' ).
      2. At least one digit.
  
  
  For example, all the following are valid numbers: ["2", "0089", "-0.1", "+3.14", "4.",
   "-.9", "2e10", "-90E3", "3e+7", "+6e-1", "53.5e93", "-123.456e789"], while the
   following are not valid numbers: ["abc", "1a", "1e", "e3", "99e2.5", "--6", "-+3", "95a54e53"].
  
  Given a string s, return true if s is a valid number.
  
  Example 1:
  
      Input: s = "0"
      Output: true
  
  Example 2:
  
      Input: s = "e"
      Output: false
  
  Example 3:
  
      Input: s = "."
      Output: false
  
  Example 4:
  
      Input: s = ".1"
      Output: true
  
  Constraints:
  
  * 1 <= s.length <= 20
  * s consists of only English letters (both uppercase and lowercase), digits (0-9), plus '+', minus '-', or dot '.'.
  """
  
  
  class Solution:
  
      def isNumber(self, s: str) -> bool:
          pass
  
  
  if __name__ == '__main__':
      cases = [("0", True), ("0089", True), ("-0.1", True), ("+3.14", True), ("-.9", True),
               ("2e10", True), ("-90E3", True), ("3e+7", True), ("+6e-1", True), ("+6e-1", True),
               ("53.5e93", True), ("-123.456e789", True), ("e", False), ("abc", False), ("1a", False),
               ("1e", False), ("e3", False), ("99e2.5", False), ("--6", False), ("-+3", False),
               ("95a54e53", False)]
  
      for case in cases:
          assert Solution().isNumber(case[0]) == case[1]
  
subject: Add leetcode 065 problem