python – Is there a Regex that allows alphabets and max 3 characters (space, period, comma) after an alphabet or some alphabets?

I know someone may have tried answering this in the past, but I couldn’t find it anywhere.

I want to write a regex that must start with some alphabet/alphabets and it only allows alphabets and 3 special characters (comma, period, space).
But the catch is, it should only allow one occurrence of these characters after the alphabet/alphabets.

So for example,

• “John,. “
• “John .,”
• “John .”
• “John ,”
• “John “
• “John,. Joe, .”

These are acceptable.

But,

• “John,..” // has 2 periods
• “John.,.” // has 2 periods
• “John,.,.,. ” // has more than one occurrence of period and comma
• “,. John” // starts with a character
• “John , .” // has 2 spaces

These are not acceptable.

I’ve tried a bunch of regex expressions but none of them can ensure 1 occurence of each character after some text.

This is the regex I’ve gotten so far but it doesn’t allow “John.,” or “John,.John”

/^[a-zA-Z]+([,.\s](?![,.\s]))?[a-zA-Z\s]*$