input: Write a python function to increment a global variable and generate a security token using MD5 hashing.
  assert increment_and_generate_token() == 'd41d8cd98f00b204e9800998ecf8427e'
  assert increment_and_generate_token() == 'd41d8cd98f00b204e9800998ecf8427e'
  assert increment_and_generate_token() == 'd41d8cd98f00b204e9800998ecf8427e'
output: import hashlib
  
  global_variable = 0
  
  def increment_and_generate_token():
      global global_variable
      global_variable += 1
      token = hashlib.md5(str(global_variable).encode()).hexdigest()
      return token