code: def poisson(lam=1.0, size=None):
      return ivy.poisson(lam=lam, shape=size)
  
imports: import ivy
  from ivy.functional.frontends.numpy.func_wrapper import to_ivy_arrays_and_back, from_zero_dim_arrays_to_scalar
  from ivy import with_supported_dtypes
label_desc: Use image node_id 21 for calling a global function with example usage: poisson(lam, size) and returns: ivy