rm dc2 in readme

README.md

@@ -18,7 +18,7 @@ This operator select input list by simply aggregating, sorting and then filterin
 For two input lists: video urls and scores, aggregate url by reduce_function, then sort aggregated scores, then select top k results.
 
 ```python
-from towhee.dc2 import pipe, ops, DataCollection
+from towhee import pipe, ops, DataCollection
 
 p = (
     pipe.input('video_urls', 'scores') \
@@ -32,7 +32,7 @@ DataCollection(p(['a', 'a', 'c', 'a', 'b', 'b', 'c', 'c'], [2, 8, 9.3, 5, 2, 1,
 ![](mean.png)   
 
 ```python
-from towhee.dc2 import pipe, ops, DataCollection
+from towhee import pipe, ops, DataCollection
 
 p = (
     pipe.input('video_urls', 'scores') \
@@ -45,7 +45,7 @@ DataCollection(p(['a', 'a', 'c', 'a', 'b', 'b', 'c', 'c'], [2, 8, 9.3, 5, 2, 1,
 ![](mean.png) 
 
 ```python
-from towhee.dc2 import pipe, ops, DataCollection
+from towhee import pipe, ops, DataCollection
 
 p = (
     pipe.input('video_urls', 'scores') \
@@ -60,7 +60,7 @@ DataCollection(p(['a', 'a', 'c', 'a', 'b', 'b', 'c', 'c'], [2, 8, 9.3, 5, 2, 1,
 
 
 ```python
-from towhee.dc2 import pipe, ops, DataCollection
+from towhee import pipe, ops, DataCollection
 
 p = (
     pipe.input('video_urls', 'scores') \