Extracting page sizes from PDF in Python

This can be done with pypdf:

>>> from pypdf import PdfReader
>>> reader = PdfReader('example.pdf')
>>> box = reader.pages[0].mediabox
>>> box
RectangleObject([0, 0, 612, 792])
>>> box.width
Decimal('612')
>>> box.height
Decimal('792')

(Formerly known as pyPdf / PyPDF2)