code: def var_count_error(is_independent, is_plotting):
      """
      Used to format an error message which differs
      slightly in 4 places.
      """
      if is_plotting:
          v = "Plotting"
      else:
          v = "Registering plot modes"
      if is_independent:
          n, s = PlotMode._i_var_max, "independent"
      else:
          n, s = PlotMode._d_var_max, "dependent"
      return (
          "%s with more than %i %s variables " "is not supported."
      ) % (v, n, s)
  
imports: from .plot_interval import PlotInterval
  from .plot_object import PlotObject
  from .util import parse_option_string
  from sympy.core.symbol import Symbol
  from sympy.core.sympify import sympify
  from sympy.geometry.entity import GeometryEntity
  from sympy.utilities.iterables import is_sequence
label_desc: Use image node_id 1 for calling a global function with example usage: var_count_error(is_independent, is_plotting) and returns: unknown