Blender copy bones

copy_bones.py

import bpy

destination_armature = bpy.data.objects['Destination Armature']
destination_root = destination_armature.pose.bones.get("ROOT_GROUND")

source_armature = bpy.data.objects['Source Armature']
source_root = source_armature.pose.bones.get("ROOT_GROUND")

bones = []

def add_children(root):
  for child in root.children:
    if child.name == "HEAD":
      continue

    add_children(child)

    bones.append(child)

add_children(destination_root)

for bone in bones:
  if source_armature.pose.bones.get(bone.name) is None:
    continue

  crc = bone.constraints.new('COPY_ROTATION')  
  crc.target = source_armature
  crc.subtarget = bone.name
  
  clc = bone.constraints.new('COPY_LOCATION')  
  clc.target = source_armature
  clc.subtarget = bone.name
  
  ctc = bone.constraints.new('COPY_TRANSFORM')  
  ctc.target = source_armature
  ctc.subtarget = bone.name