diff --git a/bean/annotate/_supporting_fn.py b/bean/annotate/_supporting_fn.py
index 127964b..e3b34f5 100644
--- a/bean/annotate/_supporting_fn.py
+++ b/bean/annotate/_supporting_fn.py
@@ -1,5 +1,5 @@
 from copy import deepcopy
-from typing import List, Tuple
+from typing import List, Tuple, Union
 from tqdm.auto import tqdm
 from ..framework.Edit import Edit, Allele
 from ..framework.AminoAcidEdit import CodingNoncodingAllele
@@ -43,14 +43,18 @@ def filter_allele_by_pos(
 def filter_allele_by_base(
     allele: Allele,
     allowed_base_changes: List[Tuple] = None,
-    allowed_ref_base: str = None,
-    allowed_alt_base: str = None,
+    allowed_ref_base: Union[List, str] = None,
+    allowed_alt_base: Union[List, str] = None,
 ):
     """
     Filter alleles based on position and return the filtered allele and
     number of filtered edits.
     """
     filtered_edits = 0
+    if isinstance(allowed_ref_base, str):
+        allowed_ref_base = [allowed_ref_base]
+    if isinstance(allowed_alt_base, str):
+        allowed_alt_base = [allowed_alt_base]
     if (
         not (allowed_ref_base is None and allowed_alt_base is None)
         + (allowed_base_changes is None)
@@ -64,15 +68,15 @@ def filter_allele_by_base(
                 allele.edits.remove(edit)
     elif not allowed_ref_base is None:
         for edit in allele.edits.copy():
-            if edit.ref_base != allowed_ref_base:
+            if edit.ref_base not in allowed_ref_base:
                 filtered_edits += 1
                 allele.edits.remove(edit)
-            elif not allowed_alt_base is None and edit.alt_base != allowed_alt_base:
+            elif not allowed_alt_base is None and edit.alt_base not in allowed_alt_base:
                 filtered_edits += 1
                 allele.edits.remove(edit)
     else:
         for edit in allele.edits.copy():
-            if edit.alt_base != allowed_alt_base:
+            if edit.alt_base not in allowed_alt_base:
                 filtered_edits += 1
                 allele.edits.remove(edit)
     return (allele, filtered_edits)
@@ -145,7 +149,6 @@ def _map_alleles_to_filtered(
         raw_allele_counts.groupby("guide"),
         desc="Mapping alleles to closest filtered alleles",
     ):
-
         guide_filtered_allele_counts = filtered_allele_counts.loc[
             filtered_allele_counts.guide == guide, :
         ].set_index(allele_col)
diff --git a/bean/annotate/translate_allele.py b/bean/annotate/translate_allele.py
index b82414a..6310717 100644
--- a/bean/annotate/translate_allele.py
+++ b/bean/annotate/translate_allele.py
@@ -175,8 +175,8 @@ def _translate_single_codon(
 ) -> str:  # nt_seq_string: str, aa_pos: int) -> str:
     """Translate `aa_pos`-th codon of `nt_seq_string`."""
     if len(codon) != 3:
-        print("reached the end of CDS, frameshift.")
-        return "/"
+        raise ValueError("reached the end of CDS, frameshift.")
+        return ">"
     try:
         codon = "".join(codon)
         return codon_map[codon]
@@ -302,7 +302,7 @@ def edit_single(self, edit_str):
                     )
                 )
                 raise RefBaseMismatchException(
-                    f"{self.gene_name + ';' if hasattr(self, 'gene_name') else ''}ref:{self.nt[rel_pos]} at pos {rel_pos}, got edit {edit}. Gene sequence: {''.join(self.nt)}"
+                    f"{self.gene_name + ';' if hasattr(self, 'gene_name') else ''}ref:{self.nt[rel_pos]} at pos {rel_pos}, got edit {edit}."
                 )
         else:
             self.edited_nt[rel_pos] = alt_base
diff --git a/bean/annotate/utils.py b/bean/annotate/utils.py
index 97fe49b..2252187 100644
--- a/bean/annotate/utils.py
+++ b/bean/annotate/utils.py
@@ -280,6 +280,12 @@ def parse_args():
         help="Only consider edit within window provided by (edit-start-pos, edit-end-pos). If this flag is not provided, `--edit-start-pos` and `--edit-end-pos` flags are ignored.",
         action="store_true",
     )
+    parser.add_argument(
+        "--keep-indels",
+        "-i",
+        help="Include indels.",
+        action="store_true",
+    )
     parser.add_argument(
         "--filter-target-basechange",
         "-b",
diff --git a/bean/framework/ReporterScreen.py b/bean/framework/ReporterScreen.py
index 37631d5..ce56061 100644
--- a/bean/framework/ReporterScreen.py
+++ b/bean/framework/ReporterScreen.py
@@ -333,7 +333,7 @@ def __getitem__(self, index):
                         lambda slist: ".".join(slist)
                     )
                     new_uns[k] = df.loc[guides_include, adata.var._rc.unique()]
-                    #adata.var.pop("_rc")
+                    # adata.var.pop("_rc")
                 else:
                     new_uns[k] = df.loc[guides_include, adata.var.rep.unique()]
             if not isinstance(df, pd.DataFrame):
@@ -697,8 +697,8 @@ def filter_allele_counts_by_pos(
 
     def filter_allele_counts_by_base(
         self,
-        ref_base="A",
-        alt_base="G",
+        ref_base: Union[List, str] = "A",
+        alt_base: Union[List, str] = "G",
         allele_uns_key="allele_counts",
         map_to_filtered=True,
         jaccard_threshold: float = 0.5,
diff --git a/bin/bean-filter b/bin/bean-filter
index 7e6f013..128ef42 100644
--- a/bin/bean-filter
+++ b/bin/bean-filter
@@ -100,6 +100,18 @@ if __name__ == "__main__":
         allele_df_keys.append(filtered_key)
         info(f"Filtered down to {len(bdata.uns[filtered_key])} alleles.")
 
+    if len(bdata.uns[allele_df_keys[-1]]) > 0 and not args.keep_indels:
+        filtered_key = f"{allele_df_keys[-1]}_noindels"
+        info(f"Filtering out indels...")
+        bdata.uns[filtered_key] = bdata.filter_allele_counts_by_base(
+            ["A", "T", "G", "C"],
+            ["A", "T", "G", "C"],
+            map_to_filtered=False,
+            allele_uns_key=allele_df_keys[-1],
+        ).reset_index(drop=True)
+        info(f"Filtered down to {len(bdata.uns[filtered_key])} alleles.")
+        allele_df_keys.append(filtered_key)
+
     if len(bdata.uns[allele_df_keys[-1]]) > 0 and args.filter_target_basechange:
         filtered_key = (
             f"{allele_df_keys[-1]}_{bdata.base_edited_from}.{bdata.base_edited_to}"