title: How to fix AttributeError: 'Series' object has no attribute 'to_numpy'
body: <p>My output:</p>
  
  <p><img src="https://i.imgur.com/nL0LMIL.png" alt="img"></p>
  
  <pre><code>def load_data(self):
      """
      Load data from list of paths
      :return: 3D-array X and 2D-array y
      """
      X = None
      y = None
      df = pd.read_excel('data/Data.xlsx', header=None)
      for i in range(len(df.columns)):
          sentences_ = df[i].to_numpy().tolist()
          label_vec = [0.0 for _ in range(0, self.n_class)]
          label_vec[i] = 1.0
          labels_ = [label_vec for _ in range(0, len(sentences_))]
          if X is None:
              X = sentences_
              y = labels_
          else:
              X += sentences_
              y += labels_
      X, max_length = self.tokenize_sentences(X)
      X = self.word_embed_sentences(X, max_length=self.max_length)
      return np.array(X), np.array(y)
  </code></pre>
  
  <p>This is my code with pandas library as pd. When I run in Google Colab I get the following error:</p>
  
  <pre class="lang-py prettyprint-override"><code>AttributeError: 'Series' object has no attribute 'to_numpy'
  </code></pre>