code: @PUT
      @Consumes(Servlets.JSON_MEDIA_TYPE)
      @Produces(Servlets.JSON_MEDIA_TYPE)
      @Path("/guid/{guid}")
      public EntityMutationResponse partialUpdateEntityAttrByGuid(@PathParam("guid") String guid,
                                                                  @QueryParam("name") String attrName,
                                                                  Object attrValue) throws Exception {
          AtlasPerfTracer perf = null;
  
          try {
              if (AtlasPerfTracer.isPerfTraceEnabled(PERF_LOG)) {
                  perf = AtlasPerfTracer.getPerfTracer(PERF_LOG, "EntityREST.partialUpdateEntityAttrByGuid(" + guid + "," + attrName + ")");
              }
  
              return entitiesStore.updateEntityAttributeByGuid(guid, attrName, attrValue);
          } finally {
              AtlasPerfTracer.log(perf);
          }
      }
docs: *****
  Entity Partial Update - Add/Update entity attribute identified by its GUID.
  Supports only uprimitive attribute type and entity references.
  does not support updation of complex types like arrays, maps
  Null updates are not possible
  *****