Improve Python3 support in get_facturx_xml_from_pdf()

Fix the meaning of an error message

README.rst

@@ -86,6 +86,10 @@ Contributors
 Changelog
 =========
 
+* Version 1.9 dated 2020-02-11
+
+  * Improve Python3 support in get_facturx_xml_from_pdf()
+
 * Version 1.8 dated 2020-01-16
 
   * New tool facturx-webservice which implements a REST webservice using Flask to generate a Factur-X PDF invoice via a simple POST request.

facturx/_version.py

@@ -1 +1 @@
-__version__ = '1.8'
+__version__ = '1.9'

facturx/facturx.py

@@ -245,8 +245,8 @@ def get_facturx_xml_from_pdf(pdf_invoice, check_xsd=True):
     if not pdf_invoice:
         raise ValueError('Missing pdf_invoice argument')
     if not isinstance(check_xsd, bool):
-        raise ValueError('Missing pdf_invoice argument')
-    if isinstance(pdf_invoice, str):
+        raise ValueError('Bad type for check_xsd argument')
+    if isinstance(pdf_invoice, (str, bytes)):
         pdf_file = BytesIO(pdf_invoice)
     elif isinstance(pdf_invoice, file):
         pdf_file = pdf_invoice