using @bobzhang/mbtpdf/io/pdfwrite {type bobzhang/mbtpdf/io/pdfwrite}

using @bobzhang/mbtpdf/crypto/pdfcrypt {type bobzhang/mbtpdf/crypto/pdfcrypt}

using @bobzhang/mbtpdf/core/pdf {type bobzhang/mbtpdf/core/pdf}

using @bobzhang/mbtpdf/core/pdf {type bobzhang/mbtpdf/core/pdf}

using @bobzhang/mbtpdf/io/pdfread {type bobzhang/mbtpdf/io/pdfread}

using @bobzhang/mbtpdf/io/pdfreadfs {type bobzhang/mbtpdf/io/pdfreadfs}

using @bobzhang/mbtpdf/io/pdfwrite {type bobzhang/mbtpdf/io/pdfwrite}

using @bobzhang/mbtpdf/io/pdfwritefs {type bobzhang/mbtpdf/io/pdfwritefs}

using @bobzhang/mbtpdf/crypto/pdfcrypt {type bobzhang/mbtpdf/crypto/pdfcrypt}

using @bobzhang/mbtpdf/core/pdf {type bobzhang/mbtpdf/core/pdf}

async fn read_file(filename : String, revision? : Int, user_password? : String, owner_password? : String) -> 
@bobzhang/mbtpdf/core/pdf.Pdf
Pdf

async fn write_file(pdf : 
@bobzhang/mbtpdf/core/pdf.Pdf
Pdf, filename : String) -> Unit