code: func MergeBodies(base, override hcl.Body) hcl.Body {
  	return mergeBody{
  		Base:     base,
  		Override: override,
  	}
  }
docs: // MergeBodies creates a new HCL body that contains a combination of the
  // given base and override bodies. Attributes and blocks defined in the
  // override body take precedence over those of the same name defined in
  // the base body.
  //
  // If any block of a particular type appears in "override" then it will
  // replace _all_ of the blocks of the same type in "base" in the new
  // body.