[BUG] padding is not working with numpy 1.16

[Sangeon Yong]

Describe the bug
A clear and concise description of what the bug is.

x_padded = np.pad(x, ((0, 0), (left_pad, right_pad)))
TypeError: pad() missing 1 required positional argument: 'mode'

To Reproduce
Steps to reproduce the behavior:

Use TSM functions with numpy 1.16

Expected behavior
A clear and concise description of what you expected to happen.

Screenshots
If applicable, add screenshots to help explain your problem.

Desktop (please complete the following information):

• OS: [e.g. Ubuntu 20.04]
• Python version: [e.g. Python 3.7.9]
• Version [e.g. 0.3.1]

Additional context
Add any other context about the problem here.