title: TypeError: unhashable type: 'numpy.ndarray' in plt.scatter
body: <p>I don't get the following error </p>
  
  <blockquote>
    <p>TypeError: unhashable type: 'numpy.ndarray'</p>
  </blockquote>
  
  <p>I tried all the possible solution, but I can't figure it out.</p>
  
  <p>this is my array:</p>
  
  <pre><code>instances=np.array([[0,10],
                              [1,3],
                              [3,4],
                              [3,5],
                              [5,5],
                              [5,6],
                              [6,-5],
                              [5,8]])
  </code></pre>
  
  <p>and I have a loop here:</p>
  
  <pre><code>for p in instances:                
      Pred=clf.predict([p])
  
      print(p[0])    
      print(Pred)
  
      plt.scatter(p[0], p[1], s=200, marker='*', c=self.colors[Pred])
  return Pred
  </code></pre>
  
  <p>the output is this:</p>
  
  <pre><code>0    
  [0.]
  </code></pre>