"""Characters that can wrap a number, symbol or unit: `(kg)`, `[V]`, `{m}`, `"m"`, `«V»`."""
import re

OPEN_CHARS = "([{\"“«‘'"
CLOSE_CHARS = ")]}\"”»’'"

OPENERS = "[" + re.escape(OPEN_CHARS) + "]"
CLOSERS = "[" + re.escape(CLOSE_CHARS) + "]"
WRAPPERS = "[" + re.escape(OPEN_CHARS + CLOSE_CHARS) + "]"