input: Write a function to search for a character in a given string. If the character is found return True else return False.
  assert serach_char("Hello", 'l')==True
  assert serach_char("Hello", 'z')==False
  assert serach_char("Hello", 'H')==True
  assert serach_char("", 'a')==False
  assert serach_char("Hello", '')==False
output: def search_char(s, char):
      return char in s