'Parse email `part` and set it to `text_content`, `html_content` or `attachments`.'

def process_part(self, part):

    content_type = part.get_content_type()
    if (content_type == u'text/plain'):
        self.text_content += self.get_payload(part)
    elif (content_type == u'text/html'):
        self.html_content += self.get_payload(part)
    elif (content_type == u'message/rfc822'):
        self.show_attached_email_headers_in_content(part)
    elif (part.get_filename() or (u'image' in content_type)):
        self.get_attachment(part)
