code: def random_filename():
      choice_chars = string.ascii_letters + string.digits
      random_chars = [random.choice(choice_chars) for _ in range(10)]
      unique_filename = "Valid Grid " + "".join(random_chars)
      return unique_filename
  
imports: from __future__ import absolute_import
  import random
  import string
  from unittest import skip
  from chart_studio import plotly
  from chart_studio.exceptions import InputError, PlotlyRequestError
  from _plotly_utils.exceptions import PlotlyError
  from plotly.graph_objs import Scatter
  from chart_studio.grid_objs import Column, Grid
  from chart_studio.plotly import parse_grid_id_args
  from chart_studio.tests.utils import PlotlyTestCase
label_desc: Use image node_id 1 for calling a global function with example usage: random_filename() and returns: unique_filename