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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def add_attendees(self, attendees, required=True):
 """ Adds new attendees to the event. *attendees* can be a list of email addresses or :class:`ExchangeEventAttendee` objects. """


    new_attendees = self._build_resource_dictionary(attendees, required=required)

    for email in new_attendees:
      self._attendees[email] = new_attendees[email]

    self._dirty_attributes.add(u'attendees')