from pyPdf import PdfFileWriter, PdfFileReader

output = PdfFileWriter()
input = PdfFileReader(open("input.pdf", 'rb'))

for x in xrange(input.numPages):
    page = input.getPage(x)
    
    # fucking-out the upper bound
    page.mediaBox.upperLeft = (page.mediaBox.getUpperLeft_x() / 1.1,
                               page.mediaBox.getUpperLeft_y() / 1.1)
    
    # fucking-out the bottom bound
    page.mediaBox.lowerLeft = (page.mediaBox.getLowerLeft_x() + 50,
                               page.mediaBox.getLowerLeft_y() + 50)
    
    output.addPage(page)

output.write(open("output.pdf", "wb"))