import os
from launch import LaunchDescription
from launch.actions import ExecuteProcess
from launch_ros.actions import Node
from launch_ros.substitutions import FindPackageShare

def generate_launch_description():
robot_name_in_model = 'fishbot'
package_name = 'fishbot_description'
urdf_name = "fishbot_gazebo.urdf"

ld = LaunchDescription() pkg_share = FindPackageShare(package=package_name).find(package_name) urdf_model_path = os.path.join(pkg_share, f'urdf/{urdf_name}') # Start Gazebo server start_gazebo_cmd = ExecuteProcess( cmd=['gazebo', '--verbose','-s', 'libgazebo_ros_init.so', '-s', 'libgazebo_ros_factory.so'], output='screen') # Launch the robot spawn_entity_cmd = Node( package='gazebo_ros', executable='spawn_entity.py', arguments=['-entity', robot_name_in_model, '-file', urdf_model_path ], output='screen') ld.add_action(start_gazebo_cmd) ld.add_action(spawn_entity_cmd) return ld

这是我的gazebo_sim.launch.py文件，是不是错误