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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def create_symlink_job(directory, checksums, filetype, symlink_path):
 """Create a symlink-creating DownloadJob for an already downloaded file."""

    pattern = NgdConfig.get_fileending(filetype)
    filename, _ = get_name_and_checksum(checksums, pattern)
    local_file = os.path.join(directory, filename)
    full_symlink = os.path.join(symlink_path, filename)
    return DownloadJob(None, local_file, None, full_symlink)