input: Write a function to search for a character in a given string. The function should return True if the character is found in the string, otherwise return False.
  
  assert serach_char("Hello", 'l')==True
  assert serach_char("Hello", 'o')==True
  assert serach_char("Hello", 'z')==False
  assert serach_char("", 'a')==False
output: def search_char(s, c):
      return c in s