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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 merge_pdfs(pdf_names, output) -> None: """ Merges all pdfs together into a single long PDF. """

    merger = PyPDF2.PdfFileMerger()

    for filename in pdf_names:
        merger.append(filename)
    merger.write(output)
    merger.close()