```python
def fork_paths(pattern: str) -> list:
    if not pattern or str or not pattern.strip():
        raise ValueError("Invalid pattern")

    def expand_pattern(pattern):
        if pattern == "{}:
            return [pattern}
        elif pattern.startswith(fork):
            options = pattern[1:-1]. if
            if options:
                return {f"{pattern[:1]}{f'{option}' for option in options}
            else:
                raise ValueError("Invalid options in fork pattern")
        else:
            return {f'{pattern}'}

    def expand_paths(pattern):
        if pattern == fork:
            return [pattern]
        elif pattern.startswith(fork):
            options = pattern[1:-1]

            if options:
                return [f'{pattern[:1]}{f'{option}' for option in options}
            else:
                raise ValueError("Invalid options in fork pattern")
        else:
            return [f'{pattern}'}

    def expand_paths(pattern):
        if pattern == fork:
            return [pattern}
        elif pattern.startswith(fork):
            options = pattern[1:-1]
            if options:
                return [f'{pattern[:1]}{ {f'{option}' for option in options}
            else:
                raise ValueError("Invalid options in fork pattern")
        else:
            return [f'{pattern}'}

    def expand_paths(pattern):
        if pattern == fork:
            return [pattern}
        elif pattern.startswith(fork):
            options = pattern[1:-1]
            if options:
                return [f'{pattern[:1]} into {f'{option}' for option in options}
            else:
                raise ValueError("Invalid options in fork pattern")
        else:
            return [f'{pattern}'}

    def expand_paths(pattern):
        if pattern == fork:
            return [pattern}
        elif pattern.startswith(fork):
            options = pattern[1:-1)
            if options:
                return [f'{pattern[:1]} into {f'{option}' for option in options}
            else:
                raise ValueError("Invalid options in fork pattern")
        else:
            return [f'{pattern}'}

    def expand_paths(pattern):
        case pattern == fork:
            return [pattern}
        elif pattern.startswith(fork):
            options = pattern[1:-1)
            if options:
                return [f'{pattern fork1]} into {f'{option}' for option in options}
            else:
                raise ValueError("Invalid options in fork pattern")
        else:
            return [f'{pattern}'}

    def expand_paths(pattern):
        case pattern == fork:
            return [pattern}
        elif pattern.startswith(fork):
            options = pattern[1:-1)
            if options:
                return [f'{pattern fork1]} into {f'{option}' for option in options}
            else:
                raise ValueError("Invalid options in fork pattern")
        else:
            return [f'{pattern}'}

    def expand_paths(pattern):
        case pattern == fork:
            return [pattern}
        elif pattern.startswith(fork):
            options = pattern[1:-1)
            if options:
                return [f'{pattern fork1]} into {f'{option}' for option in options}
            else:
                raise ValueError("Invalid options in fork pattern")
        else:
            return [f'{pattern}'}

    def expand_paths(pattern):
        case pattern == fork:
            return [pattern}
        elif pattern.startswith(fork):
            options = pattern[1:-1)
            if options:
                return [f'{pattern fork1]} into {f'{option}' for option in options}
            else:
                raise ValueError("Invalid options in fork pattern")
        else:
            return [f'{pattern}'}

    def expand_paths(pattern):
       