code: def is_2D(self):
      functions = self.window.plot._functions
      for i in functions:
          if (
              len(functions[i].i_vars) > 1
              or len(functions[i].d_vars) > 2
          ):
              return False
      return True
  
file_path: sympy/sympy/plotting/pygletplot/plot_controller.py
imports: from pyglet.window import key
  from pyglet.window.mouse import LEFT, RIGHT, MIDDLE
  from sympy.plotting.pygletplot.util import get_direction_vectors, get_basis_vectors
label_desc: Use image node_id 9 for calling the PlotController obj's underlying member method code with example usage: obj.is_2D() and returns: True, False