I am concatenating two one dimensional numpy arrays, but I am getting the error: "TypeError: only integer scalar arrays can be converted to a scalar index". What is wrong in the code?

>>> import numpy

>>> a = numpy.array([1, 2, 3])

>>> b = numpy.array([5, 6])

>>> numpy.concatenate(a, b)

Traceback (most recent call last):

File "<stdin>", line 1, in <module>

TypeError: only integer scalar arrays can be converted to a scalar index