a small python script which generates some test data in which I want to run pairwise comparisons on. There is an unresolved error that comes up when running the `get_hd()` function

tbl_error.py

import numpy as np
import tables as tb

class Iris(tb.IsDescription):
  subject_id 		= tb.IntCol()
	iris_id			= tb.IntCol()
	database 		= tb.StringCol(5)
	is_left			= tb.BoolCol()
	is_flipped		= tb.BoolCol()
	templates		= tb.BoolCol(shape=(17, 20*480))
	masks1			= tb.BoolCol(shape=(17, 20*480))
	phasors			= tb.ComplexCol(itemsize=8, shape=(17, 20*240))
	masks2			= tb.BoolCol(shape=(17, 20*240))


def create_hdf5():
	"""
	"""
	with tb.openFile('test.h5', 'w') as f:		

		# Create and fill the table of irises
		irises = f.createTable(f.root, 'irises', Iris, 'Irises', filters=tb.Filters(1))		
		for ii in range(4620):			

			r = irises.row
			r['subject_id'] = ii
			r['iris_id'] = 0
			r['database'] = 'test'
			r['is_left'] = True
			r['is_flipped'] = False
			r['templates'] = np.empty((17, 20*480), np.bool8)
			r['masks1'] = np.empty((17, 20*480), np.bool8)
			r['phasors'] = np.empty((17, 20*240), np.complex)
			r['masks2'] = np.empty((17, 20*240), np.bool8)
			r.append()

		irises.flush()

def get_hd():
	""" 
	"""
	from itertools import combinations, izip
	
	with tb.openFile('test.h5') as f:
		irises = f.root.irises

		templates = f.root.irises.cols.templates
		masks = f.root.irises.cols.masks1

		N_irises = len(irises)		

		print '%i Comparisons' % (N_irises*(N_irises - 1)/2)
		D = np.empty((N_irises, N_irises))
		for (t1, m1, ii), (t2, m2, jj) in combinations(izip(templates, masks, range(N_irises)), 2):			
			D[ii, jj] = ii*jj

		np.save('test', D)