fix xml run parsing

psm_utils/io/xtandem.py

@@ -96,9 +96,11 @@ def __init__(self, filename: str | Path, *args, decoy_prefix="DECOY_", **kwargs)
 
     def __iter__(self):
         """Iterate over file and return PSMs one-by-one."""
+
         with tandem.read(str(self.filename)) as reader:
+            run = self._parse_run(self.filename)
             for entry in reader:
-                psm = self._parse_entry(entry)
+                psm = self._parse_entry(entry,run)
                 yield psm
 
     def _parse_peptidoform(self, peptide_entry, charge: int) -> Peptidoform:
@@ -139,7 +141,7 @@ def _parse_peptidoform(self, peptide_entry, charge: int) -> Peptidoform:
 
         return Peptidoform(proforma_seq)
 
-    def _parse_entry(self, entry) -> PSM:
+    def _parse_entry(self, entry, run:str) -> PSM:
         """Parse X!Tandem XML entry to :py:class:`~psm_utils.psm.PSM`."""
         peptide_entry = entry["protein"][0]["peptide"]
         psm = PSM(
@@ -149,7 +151,7 @@ def _parse_entry(self, entry) -> PSM:
             score=-np.log(peptide_entry["expect"]),
             precursor_mz=entry["mh"] - mass.nist_mass["H"][0][0],
             retention_time=entry["rt"],
-            run=self._parse_run(self.filename),
+            run=run
             protein_list=[entry["protein"][0]["label"]],
             source="X!Tandem",
             provenance_data={