MoveIt: set_pose_targets() doesn't plan a trajectory through a list of waypoints

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I'm working on ROS Kinetic Ubuntu 16.04, Python 2.7. Here I'm attaching the function in which I'm calculating the waypoints and planning the trajectory in MoveIT! . As parameters I have the goal pose read from keyboard in main and the step(10 for example to calculate 10 waypoints). I calculate each of them by interpolating the initial position of the end effector and the final position with linear interpolation, and interpolating the initial orientation and the final one with slerp in a loop, for a given step. I'm trying compute a trajectory with the calculated waypoints and than to execute it, but the end effector does not follow them. Does anyoane know what am I doing wrong and how can I plan it? Thanks a lot!

def go_to_pose_goal(self, goal_position_x, goal_position_y, goal_position_z, goal_roll, goal_pitch, goal_yaw, steps):
move_group = self.move_group
current_pose = self.move_group.get_current_pose().pose 
final_pose = geometry_msgs.msg.Pose() 
wpose = geometry_msgs.msg.Pose()
waypoints = []

#First we need the initial position of the eef, which is given by moveit_commander and final position(read from keyboard)
#initial position
xstart = current_pose.position.x
ystart = current_pose.position.y
zstart = current_pose.position.z
#final position
xend = goal_position_x  #from keyboard
yend = goal_position_y 
zend = goal_position_z

#orientation quaternion
quaternion = quaternion_from_euler(goal_roll, goal_pitch, goal_yaw)   #transf euler from keyboard into quaternions
final_pose.orientation.x = quaternion[0]
final_pose.orientation.y = quaternion[1]
final_pose.orientation.z = quaternion[2]
final_pose.orientation.w = quaternion[3]
quat0 = [current_pose.orientation.x, current_pose.orientation.y, current_pose.orientation.z, current_pose.orientation.w]
quat1 = [final_pose.orientation.x, final_pose.orientation.y, final_pose.orientation.z, final_pose.orientation.w]

wpose = current_pose
move_group.set_pose_target(wpose)
move_group.go(wait=True)


for i in range (steps):       #i for numbering the moves
    s = float(i+1)/(steps)    #i+1 because i=0 is the current_pose
    x = (1-s)*xstart+s*xend
    y = (1-s)*ystart+s*yend
    z = (1-s)*zstart+s*zend
    wpose.position.x = x
    wpose.position.y = y
    wpose.position.z = z
    quat = quaternion_slerp(quat0, quat1, s, 1, shortestpath=True) 
    wpose.orientation.x = quat[0] 
    wpose.orientation.y = quat[1]
    wpose.orientation.z = quat[2]
    wpose.orientation.w = quat[3]
    waypoints.append(copy.deepcopy(wpose))  #add the wpose at the end of the 'waypoints' list 

move_group.set_pose_targets(waypoints)
move_group.go(wait=True)
rospy.sleep(0.1)