some issues fixed

spectrum_fundamentals/metrics/percolator.py

@@ -40,6 +40,7 @@ class Percolator(Metric):
     FRAGMENTATION: fragmentation method, e.g. HCD, CID
     RETENTION_TIME: observed retention time
     PREDICTED_RETENTION_TIME: predicted retention time by Prosit
+    PROTEINS
     """
 
     metadata: pd.DataFrame
@@ -272,11 +273,13 @@ def add_percolator_metadata_columns(self):
         self.metrics_val["Label"] = self.target_decoy_labels
         self.metrics_val["ScanNr"] = self.metadata["SCAN_NUMBER"]
         self.metrics_val["filename"] = self.metadata["RAW_FILE"]
+        # here you should ExpMass
+        self.metrics_val["ExpMass"] = 
         self.metrics_val["Peptide"] = self.metadata["MODIFIED_SEQUENCE"].apply(lambda x: "_." + x + "._")
 
         self.metrics_val["Proteins"] = self.metadata[
-            "MODIFIED_SEQUENCE"
-        ]  # we don't need the protein ID to get PSM / peptide results, fill with peptide sequence
+            "PROTEINS"
+        ]  # added proteins column for de-duplication purposes
 
     def apply_lda_and_get_indices_below_fdr(
         self, initial_scoring_feature: str = "spectral_angle", fdr_cutoff: float = 0.01