Takes a list of pdf filenames and and output filename and merges all the input filenames into one pdf (in the order they were specified).

merge_pdfs.py

from glob import glob
import os
from pyPdf import PdfFileWriter, PdfFileReader

def merge_pdfs(pdfs, output_file, delete_originals=True):
    """ Takes a list of pdf filenames and and output filename
        and merges all the input filenames into one pdf (in
        the order they were specified
    """
    merged = PdfFileWriter()
    for pdf in pdfs:
        if os.path.exists(pdf):
            r = PdfFileReader(open(pdf, 'rb'))
            for page in range(r.getNumPages()):
                merged.addPage(r.getPage(page))

    with open(output_file, 'wb') as f:
        merged.write(f)

    if delete_originals:
        for pdf in pdfs:
            if os.path.exists(pdf):
                os.unlink(pdf)

def main():
    pdfs = glob("*.pdf")
    merge_pdfs(pdfs, "merged.pdf", False)
    
if __name__ == '__main__':
    main()