adding required argument message_from_binary_file (#43)

* adding required argument message_from_binary_file

message_from_binary_file now has a required argument `policy` 
https://docs.python.org/3/library/email.parser.html#email.message_from_binary_file

In a future version a default will be added, but as of now, calling message_from_binary_file without policy will throw an error and not work
https://docs.python.org/3/library/email.parser.html#email.parser.BytesFeedParser

Also added some code to show how to iterate through attachments and how to get attachment filename, type, extension, attachment data and attachment object

* Update template.py

template.py

@@ -16,6 +16,9 @@ except:
   from io import BytesIO
 import time
 import email
+from email import message_from_binary_file
+from email import policy
+import mimetypes
 import os
 import sys
 from socket import AF_INET, AF_INET6
@@ -114,7 +117,16 @@ class myMilter(Milter.Base):
 
   def eom(self):
     self.fp.seek(0)
-    msg = email.message_from_binary_file(self.fp)
+    msg = email.message_from_binary_file(self.fp, policy=policy.default)
+
+    #example on how to iterate through attachments
+    for attachment in msg.iter_attachments():
+      #attachment holds the attachment object so that it can be used with a new MIMEMultipart() message
+      self.log("Attachment filename is %s" % (attachment.get_filename(),))
+      self.log("Attachment content/type is %s" % (attachment.get_content_type(),))
+      data = attachment.get_content()
+      self.log("Attachment content is %s" % (data,))
+    
     # many milter functions can only be called from eom()
     # example of adding a Bcc:
     self.addrcpt('<%s>' % 'spy@example.com')