reviewed code, refactored functions in linkage.py

[bhavyapan]

changed some functions from list comprehensions to more Pythonic versions such as by using NumPy functionalities, using list comprehensions instead of for loops, and leveraging better data structures.

[bhavyapan]

• Since this file called on a lot of other modules and functions from other files, I did not want to make a lot of substantive changes in terms of changing function or variable names however seeing as some of the names are quite long and repetitive, this might be a good best practice to adopt in future iterations.
• For this week, I focused on refactoring a few of the functions in the linkage.py file that were doing repetitive tasks using loops. I focused on using better and more efficient data structures and list comprehensions wherever applicable. I also used NumPy's built in functionalities to make these more efficient.
• While the documentation in this file is quite descriptive, adding tests or checking the efficiency of the tasks being performed is a set of tasks I'd like to take on next.