can't access std_srvs

edit

i did try this: atention for type Empty into msg and srv

for import msg

from std_msgs.msg import String, Float32, Empty

for import service - without problem Empty

import std_srvs.srv

publish message

take.publish(Empty())

call service

rospy.ServiceProxy('ardrone/flattrim', std_srvs.srv.Empty())

good luck!

Verify CMakeLists.txt and package.xml Specify std_srvs

If you want to use std_srvs in one of your packages via:

from std_srvs.srv import Trigger, TriggerRequest, TriggerResponse

Make sure your CMakeLists.txt file contains references to std_srvs:

find_package(catkin REQUIRED COMPONENTS
  rospy
  std_msgs
  std_srvs # <-- HERE
  message_generation
)

generate_messages(
  DEPENDENCIES
  std_msgs
  std_srvs # <-- HERE
)

catkin_package(
  CATKIN_DEPENDS rospy std_msgs std_srvs message_runtime # <-- HERE
)

And your package.xml file contains:

<!-- standard service dependencies -->
<build_depend>std_srvs</build_depend>
<run_depend>std_srvs</run_depend>