<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def start_linear_motion(self, velocity_x_m, velocity_y_m, velocity_z_m):
 """ Start a linear motion. This function returns immediately. positive X is forward positive Y is left positive Z is up :param velocity_x_m: The velocity along the X-axis (meters/second) :param velocity_y_m: The velocity along the Y-axis (meters/second) :param velocity_z_m: The velocity along the Z-axis (meters/second) :return: """

        self._set_vel_setpoint(
            velocity_x_m, velocity_y_m, velocity_z_m, 0.0)