[Tutor] need help with a regular expression

[Kelie]

Hello,

I'm trying to write a regular expression to filter strings that meet the
following criteria:

1. Starts with 0-3 underscores;
2. Followed by one letter;
3. Then followed by 0 or more letters or digits or hyphens('-'), 
4. Ends with one letter or digit; and
5. There should not be more than one continuous hyphens.

This is what I have so far. I think it meets all the criteria except for the
last one. Haven't figured out the answer yet.

re.compile(r'_{0,3}[A-Z][A-Z0-9\-]*[A-Z0-9]')

Thank you.