[NEST Users] errors when using command"d1_pop.set({"V_m":nest.random.uniform(-80.0, -55.0)})"

Dear NEST community, Thank you so much for your previous suggestions on writing my own neuron model with NESTML. I constructed a multiple synapses version of simple integrate-and-fire ("iaf_cond_beta_multisynapse") neuron based on the existing "iaf_cond_beta" neuron model. And I did this by simply adding two synaptic channels (AMPA and NMDA) without changing the structure of the neuron model. But when I called this model on NEST to set the initial membrane potentials from a uniform distribution (from 280 to 255 mV), for example:"d1_pop.set({"V_m":nest.random.uniform(-80.0, -55.0)})", an error reporting NESTErrors.TypeMismatch: "TypeMismatch in SLI function SetStatus_id: Expected datatype: doubletype Provided datatype: parametertype" appeared. So I wonder is there any coding errors in my own neuron model, since it worked just fine when I set the initial membrane potentials to a number like -80, and how can I fix this error. Best, Zirui