title: Python3 "TypeError: not all arguments converted during string formatting"
body: <p>I'm using Flask SQLAlchemy models to make a database for my app, and I'm trying to query the database using models.Posts.query.all()
  This is my model:</p>
  
  <pre><code>class Posts(db.Model):
      post_id = db.Column(db.Integer, primary_key=True)
      title = db.Column(db.String(500), index=True)
      date = db.Column(db.Date)
      image = db.Column(db.String(500))
      post_body = db.column(db.String(10000),index=True)
      authors = db.relationship('Users', backref='authors', lazy='dynamic')
  
  def __repr__(self):
      return '' % (self.post_id, self.title, self.date, self.image)
  </code></pre>
  
  <p>And this is the error message I get:</p>
  
  <pre><code>&gt;&gt;&gt; models.Posts.query.all()
  Traceback (most recent call last):
    File "&lt;stdin&gt;", line 1, in &lt;module&gt;
    File "/Users/lisa-jd/Blog_platform/app/models.py", line 30, in __repr__
      image = db.Column(db.String(50))
  TypeError: not all arguments converted during string formatting
  </code></pre>
  
  <p>Any help would be very appreciated.</p>