Documentation branch

[rpoudel1]

Closes # .

Changes proposed in this pull request:

[tsalo]

You need to define functions with parentheses, even if they're empty. We also need to include the word "pass" when the function isn't running yet.

So instead of

def Leverage_centrality:
    """Documentation...
    """

we should have:

def Leverage_centrality():
    """Documentation...
    """
    pass

[tsalo]

Function names should be lower snake case, so Delta_centrality --> delta_centrality, Degree_centrality --> degree_centrality, Leverage_centrality --> leverage_centrality.

[tsalo]

We also don't want these extra spaces here.

[tsalo]

These changes look good, but I'll hold off on merging the PR until we consolidate some functions and address the failing tests in other work.