code: def set_v_max(self, v_max):
      if v_max is None:
          self._v_max = None
          return
      try:
          self._v_max = sympify(v_max)
          float(self._v_max.evalf())
      except TypeError:
          raise ValueError(
              "v_max could not be interpreted as a number."
          )
  
imports: from sympy.core.singleton import S
  from sympy.core.symbol import Symbol
  from sympy.core.sympify import sympify
  from sympy.core.numbers import Integer
label_desc: Use image node_id 8 for calling the PlotInterval obj's underlying member method code with example usage: obj.set_v_max(v_max) without return types