[Question] Throwing an error for incorrect binary number.

[cgyurgyik]

Hi all, I'm new to pest. I have code bit below:

num_lit = @{
      ASCII_DIGIT+ ~ "'"
      ~ ( "d" ~ ASCII_DIGIT+
        | "b" ~ ASCII_BIN_DIGIT+)
}

I want to throw a readable error if the value following "b" is not 0 or 1.
I'm sure I'm not the first to do this. Are there any examples of this?

From a google search, I saw something similar to what I'm looking for: #352
However, I can't find anything else on top of this.

Please let me know if this is the incorrect place to ask!