code: def probability_density(self, X):
          
          self.check_fit()
  
          if type(X) not in (int, float):
              raise ValueError('x must be int or float')
  
          return self.model.evaluate(X)[0]
docs: Evaluate the estimated pdf on a point.
  
          Args:
              X: `float` a datapoint.
              :type X: float
  
          Returns:
              pdf: int or float with the value of estimated pdf