in robosumo/envs/agents.py [0:0]
def set_xyz(self, xyz):
"""Set (x, y, z) position of the agent; any element can be None."""
qpos = self._env.data.qpos.ravel().copy()
start = self.qpos_start_idx
if xyz[0]: qpos[start] = xyz[0]
if xyz[1]: qpos[start + 1] = xyz[1]
if xyz[2]: qpos[start + 2] = xyz[2]
qvel = self._env.data.qvel.ravel()
self._env.set_state(qpos, qvel)