documentation: edit to clarify how to use inference.py (#3194)

Co-authored-by: Basil Beirouti <[email protected]>

Author: BasilBeirouti

doc/frameworks/tensorflow/using_tf.rst

@@ -759,7 +759,7 @@ Create Python Scripts for Custom Input and Output Formats
 ---------------------------------------------------------
 
 You can add your customized Python code to process your input and output data.
-This customized Python code must be named ``inference.py`` and specified through the ``entry_point`` parameter:
+This customized Python code must be named ``inference.py`` and is specified through the ``entry_point`` parameter:
 
 .. code::
 
@@ -769,6 +769,8 @@ This customized Python code must be named ``inference.py`` and specified through
                             model_data='s3://mybucket/model.tar.gz',
                             role='MySageMakerRole')
 
+In the example above, ``inference.py`` is assumed to be a file inside ``model.tar.gz``. If you want to use a local file instead, you must add the ``source_dir`` argument. See the documentation on `TensorFlowModel <https://sagemaker.readthedocs.io/en/stable/frameworks/tensorflow/sagemaker.tensorflow.html#sagemaker.tensorflow.model.TensorFlowModel>`_.
+
 How to implement the pre- and/or post-processing handler(s)
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^