code: def encode(self):
          
          encoder = LabelEncoder()  # encoder
          values = self.get_as_list()
          encoded = encoder.fit_transform(values)  # long list of encoded
          n_columns = len(self.matrix[0])
          n_rows = len(self.matrix)
  
          self.matrix = [
              encoded[i: i + n_columns]
              for i in range(0, n_rows * n_columns, n_columns)
          ]
  
          return encoder
docs: Encodes matrix
  
          :return: Encoder used