Why am I getting this output while using split() in numpy array?

I am running this code, and I used indices in the order of (2, 1) on purpose.

a1 = np.arange(30).reshape(5, 6)
print(a1)
a, b, c = np.split(a1, (2, 1))
print("A is\n",a)
print("B is\n",b)
print("C is\n",c)

And this is the output:

[[ 0  1  2  3  4  5]
 [ 6  7  8  9 10 11]
 [12 13 14 15 16 17]
 [18 19 20 21 22 23]
 [24 25 26 27 28 29]]
A is
 [[ 0  1  2  3  4  5]
 [ 6  7  8  9 10 11]]
B is
 []
C is
 [[ 6  7  8  9 10 11]
 [12 13 14 15 16 17]
 [18 19 20 21 22 23]
 [24 25 26 27 28 29]]

I understand that I am getting b = [] because I used indices (2, 1). But why am I getting the c output from 1st index? Thank you for your time

>Solution :

According to the documentation:

If indices_or_sections is a 1-D array of sorted integers, the entries
indicate where along axis the array is split. For example,
[2, 3] would, for axis=0, result in

 - ary[:2]
 - ary[2:3]
 - ary[3:]

I.e., your example a, b, c = np.split(a1, (2, 1)) translates to:

a = a1[:2]
b = a1[2:1]
c = a1[1:]