class_docstr: 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.
docstr: Overwrites values with MNAR placed NaN's 
docstr_tok: ["Overwrites","values","with","MNAR","placed","NaN","'s"]
code: def mnar(self):
      """Overwrites values with MNAR placed NaN's"""
      pass
  
imports: import numpy
label_desc: Use image node_id 4 for calling the Corruptor obj's underlying member method code with example usage: obj.mnar() without return types