old_contents: """
      mailthon.envelope
      ~~~~~~~~~~~~~~~~~
  
      Implements the Envelope object.
  
      :copyright: (c) 2015 by Eeo Jun
      :license: MIT, see LICENSE for details.
  """
  
  
  class Envelope(object):
      """
      Encapsulates the concept of an Envelope- a wrapper
      around some content in the form of an *enclosure*,
      and dealing with SMTP specific idiosyncracies.
  
      :param enclosure: An enclosure object to wrap around.
      :param mail_from: The "real" sender. May be omitted.
      :param rcpt_to: A list of "real" email addresses.
          May be omitted.
      """
  
      def __init__(self, enclosure, mail_from=None, rcpt_to=None):
          self.enclosure = enclosure
          self.mail_from = mail_from
          self.rcpt_to = rcpt_to
  
      @property
      def sender(self):
          return self.mail_from or self.enclosure.sender
  
      @property
      def receivers(self):
          return self.rcpt_to or self.enclosure.receivers
  
      def mime(self):
          return self.enclosure.mime()
  
      def string(self):
          return self.enclosure.string()
  
new_contents: """
      mailthon.envelope
      ~~~~~~~~~~~~~~~~~
  
      Implements the Envelope object.
  
      :copyright: (c) 2015 by Eeo Jun
      :license: MIT, see LICENSE for details.
  """
  
  
  class Envelope(object):
      """
      Enclosure adapter for encapsulating the concept of
      an Envelope- a wrapper around some content in the
      form of an *enclosure*, and dealing with SMTP
      specific idiosyncracies.
  
      :param enclosure: An enclosure object to wrap around.
      :param mail_from: The "real" sender. May be omitted.
      :param rcpt_to: A list of "real" email addresses.
          May be omitted.
      """
  
      def __init__(self, enclosure, mail_from=None, rcpt_to=None):
          self.enclosure = enclosure
          self.mail_from = mail_from
          self.rcpt_to = rcpt_to
  
      @property
      def sender(self):
          """
          Returns the real sender if set in the *mail_from*
          parameter/attribute, else returns the sender
          attribute from the wrapped enclosure.
          """
          return self.mail_from or self.enclosure.sender
  
      @property
      def receivers(self):
          """
          Returns the "real" receivers which will be passed
          to the ``RCPT TO`` command (in SMTP) if specified
          in the *rcpt_to* attribute/parameter. Else, return
          the receivers attribute from the wrapped enclosure.
          """
          return self.rcpt_to or self.enclosure.receivers
  
      def mime(self):
          """
          Returns the mime object from the enclosure.
          """
          return self.enclosure.mime()
  
      def string(self):
          """
          Returns the stringified mime object.
          """
          return self.enclosure.string()
  
subject: add docstrings [skip ci]