i am trying this but not able to run

rosrun mastering_ros_demo_pkg demo_topic_publisher
[rospack] Error: package 'mastering_ros_demo_pkg' not found
find: ‘’: No such file or directory
[rosrun] Couldn't find executable named demo_topic_publisher below 
find: ‘’: No such file or directory 

ROSPACKAGEPATH=/home/user/catkin_ws/src:/opt/ros/kinetic/share