Nvim-tree floating window

local nvim_tree = require('nvim-tree')
local gwidth = vim.api.nvim_list_uis()[1].width
local gheight = vim.api.nvim_list_uis()[1].height
local width = 60
local height = 20

nvim_tree.setup{
  view = {
    width = width,
    height = height,
    float = {
      enable = true,
      open_win_config = {
        relative = "editor",
        width = width,
        height = height,
        row = (gheight - height) * 0.4,
        col = (gwidth - width) * 0.5,
      }
    }
  }
}