Change metadata of pdf file with pypdf2

Question

I want to add a metadata key-value pair to the metadata of a pdf file.

I found a several years old answer, but I think this is way to complicated. I guess there is a

Answer 1

I was surprised to see there is no code sample for PyPDF2 when the questions is explicitly asking for PyPDF2, so here it is:

from PyPDF2 import PdfFileReader, PdfFileWriter

fin = open('source.pdf', 'rb')
reader = PdfFileReader(fin)
writer = PdfFileWriter()

writer.appendPagesFromReader(reader)
metadata = reader.getDocumentInfo()
writer.addMetadata(metadata)

# Write your custom metadata here:
writer.addMetadata({
    '/Some': 'Example'
})

fout = open('result.pdf', 'wb')
writer.write(fout)

fin.close()
fout.close()