--- certdata2pem.py	2019-10-25 21:30:36.106307900 +0200
+++ certdata2pem_new.py	2019-10-25 21:31:02.041144900 +0200
@@ -126,7 +126,7 @@
         continue
     label = labelbytes.decode('utf-8')
     serial = printable_serial(obj)
-    return label + ":" + serial
+    return urllib.parse.quote(label + "_" + serial)
 
 def write_cert_ext_to_file(f, oid, value, public_key):
     f.write("[p11-kit-object-v1]\n")
@@ -268,7 +268,7 @@
             pk_fname = "pubkey-" + fname
             fpkout = open(pk_fname, "w")
             dump_pk_command = ["openssl", "x509", "-in", cert_fname, "-noout", "-pubkey"]
-            subprocess.call(dump_pk_command, stdout=fpkout)
+            subprocess.check_call(dump_pk_command, stdout=fpkout)
             fpkout.close()
             with open (pk_fname, "r") as myfile:
                 pk=myfile.read()
@@ -276,10 +276,10 @@
             comment_fname = "comment-" + fname
             fcout = open(comment_fname, "w")
             comment_command = ["openssl", "x509", "-in", cert_fname, "-noout", "-text"]
-            subprocess.call(comment_command, stdout=fcout)
+            subprocess.check_call(comment_command, stdout=fcout)
             fcout.close()
             sed_command = ["sed", "--in-place", "s/^/#/", comment_fname]
-            subprocess.call(sed_command)
+            subprocess.check_call(sed_command)
             with open (comment_fname, "r", errors = 'replace') as myfile:
                 cert_comment=myfile.read()