input: Write a function to split a given string of words separated by commas or spaces into a list of words.
  assert words_string("Hi, my name is John") == ["Hi", "my", "name", "is", "John"]
  assert words_string("One, two, three, four, five, six") == ["One", "two", "three", "four", "five", "six"]
  assert words_string("Hi, my name") == ["Hi", "my", "name"]
  assert words_string("One,, two, three, four, five, six,") == ["One", "two", "three", "four", "five", "six"]
  assert words_string("") == []
  assert words_string("ahmed     , gamal") == ["ahmed", "gamal"]
  
output: def words_string(s):
      return [word for word in re.split(r'[,\s]+', s) if word]