def addMetadata(self, inputstream, metadata):
"""Adds metadata to a PDF document"""
reader = PdfReader(inputstream)
outputstream = ByteArrayOutputStream()
stp = PdfStamper(reader, outputstream, "\0")
meta = reader.getInfo()
for key in ('Subject', 'Author', 'Keywords', 'Title', 'Creator', 'CreationDate'):
if key in metadata:
meta.put(key, metadata[key])
stp.setMoreInfo(meta)
stp.close()
return outputstream
