post.py

from exceptions import PermissionDenied
"""
Post:

A Post is created by a particular author.
The author is able to edit the content, but other users cannot.
Any user should be able to bump the upvotes, but only once per user.
Thread:
"""

class Post:
  def __init__(self, content, author):
    """
   Creates a new thread with a title and an initial first post.
   The author of the first post at the time of thread creation is the owner of the thread.
   The owner cannot change once the thread is created.
   """
    self.content = content
    self.author = author
    self.upvotes = 0
    self.upvoted = []

  def get_author(self):
    """
   Returns the author of the post.
   """
    return self.author

  def get_content(self):
    """
   Returns the content of the post.
   """
    return self.content

  def get_upvotes(self):
    """
   Returns a single integer representing the total number of upvotes.
   """
    return self.upvotes

  def set_content(self, content, by_user):
    """
   Called when the given user wants to update the content.
   * raises PermissionDenied if the given user is not the author.
   """
    if by_user != self.author:
        raise PermissionDenied
    else:
        self.content = content

  def upvote(self, by_user):
    """
   Called when the given user wants to upvote this post.
   A user can only perform an up vote *once*.
   """
    if by_user not in self.upvoted:
        self.upvoted.append(by_user)
        self.upvotes += 1