Modifying code to use, `typing` module.

[czgdp1807]

Description of the problem

From now onwards, the new code should use typing module and the existing code in master should be modified to use typing module.

Example of the problem

References/Other comments

See, https://docs.python.org/3/library/typing.html

[mightomi]

I like to take this issue and solve it.

[czgdp1807]

Sure, go ahead.

[shubhanshu-coder]

i am intersting in this project like to solve the issue.

[czgdp1807]

Sure. Please read https://github.com/codezonediitj/pydatastructs/wiki/Issue-Policy

[ishitakapoor26]

/assign

[AABur]

@czgdp1807, can you explain what you want to achieve using the typing module? Using the typing module allows using type annotations in code. This does not affect runtime.
Please show some examples of existing code that needs to be replaced given the use of typing.