code: def fit_transform(self, X, y=None):
          
  
          self.ecdfs = [None] * X.shape[1]
  
          for col in range(X.shape[1]):
              self.ecdfs[col] = ECDF(X[:, col])
              X[:, col] = self._transform_col(X[:, col], col)
  
          return X
docs: Normalize numerical columns.
  
          Args:
              X (numpy.array) : numerical columns to normalize
  
          Returns:
              X (numpy.array): normalized numerical columns