[inference] removed redundancy init_batch
diff --git a/colossalai/inference/core/request_handler.py b/colossalai/inference/core/request_handler.py
index 585f879456f2..80d77d09759f 100644
--- a/colossalai/inference/core/request_handler.py
+++ b/colossalai/inference/core/request_handler.py
@@ -171,7 +171,7 @@ def schedule(self):
         if self.running_list.ready_for_prefill():
             for seq in self.running_list.prefill:
                 seq.mark_running()
-            self.prefill_batch.init_batch(self.running_list.prefill)
+            self.prefill_batch.add_seqs(self.running_list.prefill)
             return self.prefill_batch
 
         if not self.running_batch.is_empty:
diff --git a/colossalai/inference/struct.py b/colossalai/inference/struct.py
index 22b5b5a3ab2f..766e54ab1415 100644
--- a/colossalai/inference/struct.py
+++ b/colossalai/inference/struct.py
@@ -188,24 +188,6 @@ def __post_init__(self):
         if self.fd_inter_tensor is None:
             self.fd_inter_tensor = FDIntermTensors()
 
-    def init_batch(self, seqs: List["Sequence"] = None):
-        """
-        Initializes inference batches by input sentence list.
-
-        Args:
-            seqs (List["Sequence"]): List of input sequence.
-        """
-
-        if seqs is not None:
-            if not isinstance(seqs, list):
-                seqs = [seqs]
-            for seq in seqs:
-                if seq in self.sequences_set:
-                    logger.warning(f"The sequence(request_id {seq.request_id}) is already in sequences_set.")
-                    continue
-
-                self.sequences_set.add(seq)
-
     def init_fd_tensors(self):
         if not self.fd_inter_tensor.is_initialized:
             self.fd_inter_tensor.initialize(
@@ -273,19 +255,19 @@ def abort_seq(self, seq: "Sequence") -> "Sequence":
         self.sequences_set.discard(seq)
         return seq
 
-    def add_seqs(self, seqs: List["Sequence"]) -> None:
+    def add_seqs(self, seqs: Union[Sequence, List[Sequence]]) -> None:
         """
         Add new sequence to batch
 
         Args:
             seqs (List["Sequence"]): The list of new sequences.
         """
-
-        if not isinstance(seqs, list):
+        # covnert single sequence to list
+        if isinstance(seqs, Sequence):
             seqs = [seqs]
 
         for seq in seqs:
-            if self.sequences_set and seq in self.sequences_set:
+            if seq in self.sequences_set:
                 logger.warning(f"The sequence(request_id {seq.request_id}) is already in sequences_set.")
                 continue
             self.sequences_set.add(seq)
diff --git a/tests/test_infer/test_config_and_struct.py b/tests/test_infer/test_config_and_struct.py
index 16f5bcc7f0b2..e0736518ca95 100755
--- a/tests/test_infer/test_config_and_struct.py
+++ b/tests/test_infer/test_config_and_struct.py
@@ -60,9 +60,8 @@ def check_config_and_inference():
         num_heads=2,
         head_dim=128,
     )
-    batch.init_batch([sequence])
-    batch.add_seqs([sequence2, sequence3])
     batch.add_seqs([sequence])
+    batch.add_seqs([sequence2, sequence3])
 
     assert batch.is_empty == False
     assert batch.get_batch_size() == 3

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