text: """ impyute.dataset.corrupt """
  import numpy as np
  
  
  class Corruptor:
      """ Adds missing values to a complete dataset.
  
      Attributes
      ----------
      data: np.ndarray
          Matrix of values with no NaN's that you want to add NaN's to.
      thr: float (optional)
          The percentage of null values you want in your dataset, a number
          between 0 and 1.
  
      Methods
      -------
      mcar()
          Overwrite values with MCAR placed NaN's.
      mar()
          Overwrite values with MAR placed NaN's.
      mnar()
          Overwrite values with MNAR placed NaN's.
  
      """
      def __init__(self, data, thr=0.2, dtype=np.float):
          self.dtype = data.dtype
          self.shape = np.shape(data)
          self.data = data.astype(dtype)
          self.thr = thr
  
      def mcar(self):
          """ Overwrites values with MCAR placed NaN's """
          data_1d = self.data.flatten()
          n_total = len(data_1d)
          nan_x = np.random.choice(range(n_total),
                                    size=int(self.thr*n_total),
                                    replace=False)
          for x_i in nan_x:
              data_1d[x_i] = np.nan
          output = data_1d.reshape(self.shape)
          return output
  
      def mar(self):
          """ Overwrites values with MAR placed NaN's """
          pass
  
      def mnar(self):
          """ Overwrites values with MNAR placed NaN's """
          pass
  
      def complete(self):
          """ Do nothing to the data """
          output = self.data
          return output
  