diff --git a/swh/indexer/metadata_dictionary/python.py b/swh/indexer/metadata_dictionary/python.py
index 8a1b2ee..bd563ca 100644
--- a/swh/indexer/metadata_dictionary/python.py
+++ b/swh/indexer/metadata_dictionary/python.py
@@ -1,75 +1,78 @@
 # Copyright (C) 2018-2019  The Software Heritage developers
 # See the AUTHORS file at the top-level directory of this distribution
 # License: GNU General Public License version 3, or any later version
 # See top-level LICENSE file for more information
 
 import email.parser
 import email.policy
 import itertools
 
 from swh.indexer.codemeta import CROSSWALK_TABLE
 from swh.indexer.namespaces import SCHEMA
 
 from .base import DictMapping, SingleFileIntrinsicMapping
 
 _normalize_pkginfo_key = str.lower
 
 
 class LinebreakPreservingEmailPolicy(email.policy.EmailPolicy):
     def header_fetch_parse(self, name, value):
         if hasattr(value, "name"):
             return value
         value = value.replace("\n        ", "\n")
         return self.header_factory(name, value)
 
 
 class PythonPkginfoMapping(DictMapping, SingleFileIntrinsicMapping):
     """Dedicated class for Python's PKG-INFO mapping and translation.
 
     https://www.python.org/dev/peps/pep-0314/"""
 
     name = "pkg-info"
     filename = b"PKG-INFO"
     mapping = {
         _normalize_pkginfo_key(k): v
         for (k, v) in CROSSWALK_TABLE["Python PKG-INFO"].items()
     }
     string_fields = [
         "name",
         "version",
         "description",
         "summary",
         "author",
         "author-email",
     ]
 
     _parser = email.parser.BytesHeaderParser(policy=LinebreakPreservingEmailPolicy())
 
     def translate(self, content):
         msg = self._parser.parsebytes(content)
         d = {}
         for (key, value) in msg.items():
             key = _normalize_pkginfo_key(key)
             if value != "UNKNOWN":
                 d.setdefault(key, []).append(value)
         metadata = self._translate_dict(d, normalize=False)
-        if SCHEMA.author in metadata or SCHEMA.email in metadata:
+
+        author_name = metadata.pop(SCHEMA.author, None)
+        author_email = metadata.pop(SCHEMA.email, None)
+        if author_name or author_email:
             metadata[SCHEMA.author] = {
                 "@list": [
                     {
                         "@type": SCHEMA.Person,
-                        SCHEMA.name: metadata.pop(SCHEMA.author, [None])[0],
-                        SCHEMA.email: metadata.pop(SCHEMA.email, [None])[0],
+                        SCHEMA.name: author_name,
+                        SCHEMA.email: author_email,
                     }
                 ]
             }
         return self.normalize_translation(metadata)
 
     def normalize_home_page(self, urls):
         return [{"@id": url} for url in urls]
 
     def normalize_keywords(self, keywords):
         return list(itertools.chain.from_iterable(s.split(" ") for s in keywords))
 
     def normalize_license(self, licenses):
         return [{"@id": license} for license in licenses]