def passes_all_checks(i: Index) -> bool:
            """
            Returns:
                True iff ALL of the conditions listed in the 'Transformations'
                section of this classes' docstring would be met by returning @i.
            """
            is_space = string[i] == " "
            is_split_safe = is_valid_index(i - 1) and string[i - 1] in SPLIT_SAFE_CHARS

            is_not_escaped = True
            j = i - 1
            while is_valid_index(j) and string[j] == "\\":
                is_not_escaped = not is_not_escaped
                j -= 1

            is_big_enough = (
                len(string[i:]) >= self.MIN_SUBSTR_SIZE
                and len(string[:i]) >= self.MIN_SUBSTR_SIZE
            )
            return (
                (is_space or is_split_safe)
                and is_not_escaped
                and is_big_enough
                and not breaks_unsplittable_expression(i)
            )

            Returns:
                True iff ALL of the conditions listed in the 'Transformations'
                section of this classes' docstring would be met by returning @i.
            
src/black/trans.py