Update README

Signed-off-by: Jael Gu <mengjia.gu@zilliz.com>

README.md

@@ -33,12 +33,10 @@ to generate a text embedding for the sentence "Hello, world.".
 *Write the pipeline*:
 
 ```python
-from towhee import dc
+import towhee
 
-
-dc.stream(["Hello, world."]) \
-  .text_embedding.longformer(model_name=c"allenai/longformer-base-4096") \
-  .to_list()
+towhee.dc(["Hello, world."]) \
+      .text_embedding.longformer(model_name=c"allenai/longformer-base-4096")
 ```
 
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