code: def test_unparametrized_operator():
      # Tests that an operator cannot be defined without parameters.
      with raises(SignatureError):
  
          @operator
          def f(x: Field):
              return x
  
imports: import jax
  from jax import grad, jit, make_jaxpr
  from jax import numpy
  from plum.function import NotFoundLookupError
  from pytest import mark, raises
  from jaxdf import *
  from jaxdf.operators.dummy import dummy, yummy
  from jaxdf.signatures import SignatureError
label_desc: Use image node_id 7 for calling a global function with example usage: test_unparametrized_operator() and returns: x