error when running -> gulp --target=NRF52_DK

error

(mbed) ❯ gulp --target=NRF52_DK
[21:55:54] Using gulpfile ~/dev/mbed-js-example/Gulpfile.js
[21:55:54] Starting 'make-build-dir'...
[21:55:54] Starting 'bundle'...
[21:55:54] Starting 'ignorefile'...
[21:55:54] Finished 'make-build-dir' after 46 ms
[21:55:54] Starting 'makefile'...
$ mkdir -p ./build/source
[21:55:54] Finished 'ignorefile' after 33 ms
[21:55:54] Finished 'makefile' after 14 ms
[21:55:54] Starting 'get-jerryscript'...
[21:55:54] Finished 'get-jerryscript' after 12 ms
[21:55:54] Starting 'getlibs'...
$                    if [ ! -d "./jerryscript/" ]; then                        git clone https://github.com/jerryscript-project/jerryscript;                        cd jerryscript;                        git checkout 65c32f6a3bad963d14ac7a1992451a4bf494ab06;                        cd ..;                        pip install -r jerryscript/targets/mbedos5/tools/requirements.txt;                    fi;
[21:55:54] Finished 'bundle' after 132 ms
$ make getlibs
mbed config root .
[mbed] . now set as default root in program "mbed-js-example"
mbed toolchain GCC_ARM
[mbed] GCC_ARM now set as default toolchain in program "mbed-js-example"
mbed target NRF52_DK
[mbed] NRF52_DK now set as default target in program "mbed-js-example"
mbed deploy
[mbed] Updating library "mbed-os" to rev #d5de476f74dd
[21:55:56] Finished 'getlibs' after 2.18 s
[21:55:56] Starting 'cppify'...
[21:55:56] Finished 'cppify' after 38 ms
[21:55:56] Starting 'build'...
[21:55:57] Found no native packages.
$ make BOARD=NRF52_DK EXTRAS=
[21:55:57] build/make
[21:55:57] Finished 'build' after 1.22 s
[21:55:57] Starting 'default'...
[21:55:57] Finished 'default' after 7.76 μs
cd jerryscript/targets/mbedos5 && pip install -r tools/requirements.txt && rm -f source/js_encoded.cpp && rm -f source/pins.cpp && rm -f source/main.cpp && make BOARD=NRF52_DK EXTRA_SRC="../../../source" EXTERN_BUILD_DIR=../../../out/NRF52_DK NO_JS=1
Requirement already satisfied: pycparser in /Users/mca/.virtualenvs/mbed/lib/python2.7/site-packages (from -r tools/requirements.txt (line 1))
Requirement already satisfied: simpleeval in /Users/mca/.virtualenvs/mbed/lib/python2.7/site-packages (from -r tools/requirements.txt (line 2))
Requirement already satisfied: pycparserext in /Users/mca/.virtualenvs/mbed/lib/python2.7/site-packages (from -r tools/requirements.txt (line 3))
Requirement already satisfied: ply>=3.4 in /Users/mca/.virtualenvs/mbed/lib/python2.7/site-packages (from pycparserext->-r tools/requirements.txt (line 3))
python tools/generate_pins.py NRF52_DK
mbed config root .
[mbed] . now set as default root in program "mbed-js-example"
mbed toolchain GCC_ARM
[mbed] GCC_ARM now set as default toolchain in program "mbed-js-example"
mbed target NRF52_DK
[mbed] NRF52_DK now set as default target in program "mbed-js-example"
mbed deploy
[mbed] Updating library "mbed-os" to rev #d5de476f74dd
mbed target NRF52_DK
[mbed] NRF52_DK now set as default target in program "mbed-js-example"
mbed compile -j0 --source . --source ../../ --source ../../../source --build ../../../out/NRF52_DK -D "CONFIG_MEM_HEAP_AREA_SIZE=(1024*16)" -t GCC_ARM
[ERROR] Attribute 'default_build' not found in target 'NRF52_DK'
[mbed] ERROR: "python" returned error code 1.
[mbed] ERROR: Command "python -u /Users/mca/dev/mbed-js-example/.temp/tools/make.py -t GCC_ARM -m NRF52_DK --source . --source ../../ --source ../../../source --build ../../../out/NRF52_DK -j0 -D CONFIG_MEM_HEAP_AREA_SIZE=(1024*16)" in "/Users/mca/dev/mbed-js-example/build/jerryscript/targets/mbedos5"
---
make[1]: *** [all] Error 1
make: *** [all] Error 2
events.js:160
      throw er; // Unhandled 'error' event
      ^

Error: Command `make BOARD=NRF52_DK EXTRAS=` exited with code 2
    at ChildProcess.handleSubShellExit (/Users/mca/dev/mbed-js-example/node_modules/gulp-run/command.js:166:13)
    at ChildProcess.g (events.js:291:16)
    at emitTwo (events.js:106:13)
    at ChildProcess.emit (events.js:191:7)
    at Process.ChildProcess._handle.onexit (internal/child_process.js:215:12)