Switch to the next or previous file group in Sublime Text

Default (Linux).sublime-keymap

[
    // Add to your own custom key bindings file using 'Preferences > Key Bindings'; set the keys as
    // desired for your own use.
    { "keys": ["super+t"],
      "command": "switch_group",
      "args": {"forward": true }
    },

    { "keys": ["super+ctrl+t"],
      "command": "switch_group",
      "args": {"forward": false }
    },    
]

group_switch.py

import sublime
import sublime_plugin


class SwitchGroupCommand(sublime_plugin.WindowCommand):
  """
  Switches the focus to either the next or previous file group from the current
  one. When forward is true, the focus shifts to the next group, and when false
  it goes to the previous group. Going past the "end" of the list of groups
  wraps around to the other end.
  """
  def run(self, forward=True):
    # Alias the window the command is in to make the text shorter
    w = self.window

    # If we're moving forward, the group goes up by 1; otherwise down by 1
    adjustment = 1 if forward else -1

    # Add our adjustment to the current group number, and keep it in range of
    # the number of groups that exist
    new_group = (w.active_group() + adjustment) % w.num_groups()

    # Focus the group
    w.focus_group(new_group)