rig.py

import bpy

context = bpy.context
scene = context.scene

def bones():
    active = context.active_pose_bone
    if active is context.selected_pose_bones[0]:
        return [active, context.selected_pose_bones[1]]
    return [active, context.selected_pose_bones[0]]    

def addRotationConstraint():
    [target, subtarget] = bones()
    crc = target.constraints.new('COPY_ROTATION')

    crc.target = context.selected_objects[0]
    crc.subtarget = subtarget.name
    crc.use_y = False
    crc.use_z = False
    crc.use_offset = True
    crc.owner_space = "LOCAL"
    crc.target_space = "LOCAL"
    

def lockRotation():
    for b in context.selected_pose_bones:
        b.lock_rotation[1] = True
        b.lock_rotation[2] = True


lockRotation()
#addRotationConstraint()