diff --git a/docs/installation/env_requirement.rst b/docs/installation/env_requirement.rst
index c482712418b1e0afb92970ce0a55bb7226e82ed9..6946a524e22f3284f585f46f9e71fa9604f84176 100644
--- a/docs/installation/env_requirement.rst
+++ b/docs/installation/env_requirement.rst
@@ -30,6 +30,9 @@ Required dependencies
     * - sh
       - pip install -I sh==1.12.14
       - 1.12.14
+    * - Numpy
+      - pip install -I numpy==1.14.0
+      - Required by model validation
 
 Optional dependencies
 ---------------------
@@ -52,15 +55,12 @@ Optional dependencies
     * - Docker
       - `docker installation guide <https://docs.docker.com/install/linux/docker-ce/ubuntu/#set-up-the-repository>`__
       - Required by docker mode for Caffe model
-    * - Numpy
-      - pip install -I numpy==1.14.0
-      - Required by model validation
     * - Scipy
       - pip install -I scipy==1.0.0
       - Required by model validation
     * - FileLock
       - pip install -I filelock==3.0.0
-      - Required by Android run
+      - Required by run on Android
 
 .. note::
 
diff --git a/docs/user_guide/advanced_usage.rst b/docs/user_guide/advanced_usage.rst
index 1f536bff07e3a18866f26a7761b90a312be22887..141cedc42ce6976f3f8c73ae4ef480499468e360 100644
--- a/docs/user_guide/advanced_usage.rst
+++ b/docs/user_guide/advanced_usage.rst
@@ -160,6 +160,17 @@ There are two common advanced use cases:
                    ├── mobilenet-v1.a
                    └── mobilenet_v1.data
 
+             # model_graph_format: code
+             # model_data_format: code
+
+             builds
+               ├── include
+               │   └── mace
+               │       └── public
+               │           ├── mace_engine_factory.h
+               │           └── mobilenet_v1.h
+               └── model
+                   └── mobilenet-v1.a
 
     * **3. Deployment**
         * Link `libmace.a` and `${library_name}.a` to your target.
@@ -182,7 +193,7 @@ There are two common advanced use cases:
             // Create Engine from compiled code
             create_engine_status =
                 CreateMaceEngineFromCode(model_name.c_str(),
-                                         nullptr,
+                                         model_data_file, // empty string if model_data_format is code
                                          input_names,
                                          output_names,
                                          device_type,
diff --git a/tools/converter.py b/tools/converter.py
index c13d7e835a33a62738a0b380c099ca32eb4eb36f..e234f4a64550091c98cc7985da8269942f078624 100644
--- a/tools/converter.py
+++ b/tools/converter.py
@@ -13,7 +13,6 @@
 # limitations under the License.
 
 import argparse
-import filelock
 import glob
 import hashlib
 import os
diff --git a/tools/sh_commands.py b/tools/sh_commands.py
index a3617224eb7b433ac253280d03864bf46edc02dd..1331a1e075eafb22e2ac936fa81a9730c78cfd44 100644
--- a/tools/sh_commands.py
+++ b/tools/sh_commands.py
@@ -13,7 +13,6 @@
 # limitations under the License.
 
 import falcon_cli
-import filelock
 import glob
 import logging
 import numpy as np
@@ -69,10 +68,12 @@ def device_lock_path(serialno):
 
 
 def device_lock(serialno, timeout=3600):
+    import filelock
     return filelock.FileLock(device_lock_path(serialno), timeout=timeout)
 
 
 def is_device_locked(serialno):
+    import filelock
     try:
         with device_lock(serialno, timeout=0.000001):
             return False