Running a python script at build time in CMake, requires no dependencies - cmake

Question

I have a python script h2py.py that converts a header file .hpp to .py file.
I want this python script to be run every time I build my project with CMake.
There is no other project or file that has a dependency on the file generated by the script.
So far I have tried this:
find_package(PythonInterp REQUIRED)
add_custom_target(
run ALL
COMMAND ${PYTHON_EXECUTABLE} ${CMAKE_CURRENT_SOURCE_DIR}/include/converter/h2py.py ${CMAKE_CURRENT_SOURCE_DIR}/include/converter/
COMMENT "Converting .hpp file to .py file"
)
add_dependencies(converter run)
But this does not generate the .py equivalent of the .hpp file (specified within the script)
EDIT : When I run the python script h2py.py in a terminal, it generates the .py eqvivalent of the .hpp file, just as intended. But it does not generate the .py file when I run the CMake file.
This is the whole CMake file:
cmake_minimum_required(VERSION 2.8.3)
project(converter)
set(CMAKE_BUILD_TYPE release)
add_compile_options(-std=c++11)
## Find catkin macros and libraries
## if COMPONENTS list like find_package(catkin REQUIRED COMPONENTS xyz)
## is used, also find other catkin packages
find_package(catkin REQUIRED
roscpp
geometry_msgs
eigen_conversions
std_msgs
tf_conversions
tf
genmsg
message_generation
sensor_msgs
rospy
gazebo_msgs
)
catkin_package(
#DEPENDS Eigen libpcl-all-dev gnuplot
CATKIN_DEPENDS roscpp sensor_msgs tf_conversions tf geometry_msgs message_generation
INCLUDE_DIRS include
LIBRARIES ${PROJECT_NAME}
)
###########
## Build ##
###########
## Specify additional locations of header fils
## Your package locations should be listed before other locations
include_directories(
include
${catkin_INCLUDE_DIRS}
)
## Declare a C++ library
add_library(${PROJECT_NAME}
src/${PROJECT_NAME}/motion_covariance.cpp
src/${PROJECT_NAME}/tf_utils.cpp
)
target_link_libraries(${PROJECT_NAME} ${catkin_LIBRARIES} ${Boost_LIBRARIES} )
find_package(PythonInterp REQUIRED)
add_custom_target(
run ALL
COMMAND ${PYTHON_EXECUTABLE} ${CMAKE_CURRENT_SOURCE_DIR}/include/converter/h2py.py ${CMAKE_CURRENT_SOURCE_DIR}/include/converter/
COMMENT "Converting .hpp file to .py file"
)
add_dependencies(converter run)

Answer 1

As per #Tsyvarev's comment, problem was solved by setting the WORKING_DIRECTORY option to the add_custom_command!