diff --git a/python/npcomp/__init__.py b/python/npcomp/__init__.py
index e69de29bb..f5a28b832 100644
--- a/python/npcomp/__init__.py
+++ b/python/npcomp/__init__.py
@@ -0,0 +1,6 @@
+# Top-level symbols.
+from .exporter import *
+from .types import *
+
+from . import tracing
+from . import utils
diff --git a/python/npcomp/tracing/__init__.py b/python/npcomp/tracing/__init__.py
index e69de29bb..b0bc4d378 100644
--- a/python/npcomp/tracing/__init__.py
+++ b/python/npcomp/tracing/__init__.py
@@ -0,0 +1,3 @@
+# Module level symbols.
+from .context import *
+from .mlir_trace import *
diff --git a/python/npcomp/utils/__init__.py b/python/npcomp/utils/__init__.py
new file mode 100644
index 000000000..8ba4ae08d
--- /dev/null
+++ b/python/npcomp/utils/__init__.py
@@ -0,0 +1 @@
+from . import test_utils as test
diff --git a/python/npcomp/utils/test_utils.py b/python/npcomp/utils/test_utils.py
index 7427c3585..19d43f7cf 100644
--- a/python/npcomp/utils/test_utils.py
+++ b/python/npcomp/utils/test_utils.py
@@ -10,6 +10,8 @@ import sys
 
 _disable_var = "NPCOMP_DISABLE_FILECHECK"
 _filecheck_binary_var = "FILECHECK_BINARY"
+_redirect_io = None
+_redirect_context = None
 
 def is_filecheck_disabled():
   return _disable_var in os.environ
diff --git a/python/samples/simple_ufunc.py b/python/samples/simple_ufunc.py
new file mode 100644
index 000000000..8c3db3347
--- /dev/null
+++ b/python/samples/simple_ufunc.py
@@ -0,0 +1,33 @@
+#  Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+#  See https://llvm.org/LICENSE.txt for license information.
+#  SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+import numpy as np
+import npcomp as npc
+from npcomp.types import *
+
+def simple_mul(a: np.ndarray, b: np.ndarray) -> np.ndarray:
+  return a * b + a + b
+
+# TODO: Implement subclassing and deriving constraints by run
+exp = npc.Exporter()
+exp.simple_mul = simple_mul
+exp.simple_mul.sig.args["a"] += Shape(1, 4)
+exp.simple_mul.sig.args["a"] += DynamicDim(0)
+exp.simple_mul.sig.args["a"] += DType(np.float32)
+exp.simple_mul.sig.args["b"] += Shape(1)
+exp.simple_mul.sig.args["b"] += DType(np.float32)
+exp.simple_mul.sig.result += Shape(1, 4)
+exp.simple_mul.sig.result += DynamicDim(0)
+exp.simple_mul.sig.result += DType(np.float32)    
+
+mb = npc.tracing.ModuleBuilder()
+mb.trace(exp.simple_mul)
+# CHECK: func @simple_mul(%arg0: tensor<?x4xf32>, %arg1: tensor<1xf32>) -> tensor<?x4xf32> {
+# CHECK:  %0 = numpy.ufunc_call @numpy.multiply(%arg0, %arg1) : (tensor<?x4xf32>, tensor<1xf32>) -> tensor<*x!numpy.any_dtype>
+# CHECK:  %1 = numpy.ufunc_call @numpy.add(%0, %arg0) : (tensor<*x!numpy.any_dtype>, tensor<?x4xf32>) -> tensor<*x!numpy.any_dtype>
+# CHECK:  %2 = numpy.ufunc_call @numpy.add(%1, %arg1) : (tensor<*x!numpy.any_dtype>, tensor<1xf32>) -> tensor<*x!numpy.any_dtype>
+# CHECK:  %3 = numpy.narrow %2 : (tensor<*x!numpy.any_dtype>) -> tensor<?x4xf32>
+# CHECK:  return %3 : tensor<?x4xf32>
+# CHECK: }
+print(mb.module.to_asm())