code: def test_eager_subs_variable():
      v = Variable("v", Reals[3])
      point = Tensor(randn(3))
      d = Delta("foo", v)
      assert d(v=point) is Delta("foo", point)
  
file_path: funsor/test/test_delta.py
imports: import pytest
  import funsor.ops
  from funsor.delta import Delta
  from funsor.domains import Real, Reals
  from funsor.tensor import Tensor, numeric_array
  from funsor.terms import Number, Variable
  from funsor.testing import assert_close, check_funsor, randn
label_desc: Use image node_id 1 for calling a global function with example usage: test_eager_subs_variable() without return types