"List levels" node

Слиты nikitronn запросил слияние list_levels_node в master

Created by: portnov

Addressed problem description

"List Del Levels" node has too un-intuitive UI :) Also, there is no standard way to put additional pair of square brackets at arbitrary nesting level

Solution description

This node allows the user to manipulate with nesting structure of data by setting checkboxes. It allows to:

  • Remove a level of nesting by concatenating nested lists of some level, or
  • Add a level of nesting by adding another pair of square brackets around nested list of some level, or
  • do both things at the same or at different nesting levels.

This node works with nested lists or tuples. Numpy arrays are considered to be atomic objects.

Screenshot_20201205_115715 Screenshot_20201205_115733 Screenshot_20201205_115758 Screenshot_20201205_115816 Screenshot_20201205_115837 Screenshot_20201205_115901 Screenshot_20201205_115919

Screenshot_20201205_134351

Preflight checklist

Put an x letter in each brackets when you're done this item:

  • Code changes complete.
  • Code documentation complete.
  • Documentation for users complete (or not required, if user never sees these changes).
  • Manual testing done.
  • Unit-tests implemented.
  • Ready for merge.