code: def set_v_min(self, v_min):
      if v_min is None:
          self._v_min = None
          return
      try:
          self._v_min = sympify(v_min)
          float(self._v_min.evalf())
      except TypeError:
          raise ValueError(
              "v_min 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 6 for calling the PlotInterval obj's underlying member method code with example usage: obj.set_v_min(v_min) without return types