IncompleteParseError

[TheBicPen]

I'm getting an IncompleteParseError creating a Grammar object on a very simple grammar that seems valid to me:

IncompleteParseError
Rule 'rules' matched in its entirety, but it didn't consume all the text. The non-matching portion of the text begins with '/ "5"
    ' (line 2, column 21).

And the grammar:

Grammar(r"""
    value = "[" "]" / "5"
    """
)