Fold or Unfold all code in current file with VIM
VIM Help Info
Input :help fold
to check VIM manual.
zo: open current folder
zc: close current folder
zR: open all folders
zM: close all folders
References:
Found a Quora link, https://www.quora.com/How-can-you-fold-and-unfold-Python-code-in-Vim