import shutil


def command_exists(command: str) -> bool:
    """
    Checks whether some external utility is installed and accessible to this script.

    Args:
        command: The name of the binary/command to look for. It must be a single name; arguments and shell command lines
            are not accepted.

    Returns:
        True if the command exists and is accessible (as per `which`).
    """
    return shutil.which(command) is not None