Create a tool to check nanobeacon flag in trigger mask

src/km3io/tools.py

@@ -536,3 +536,14 @@ def is_3dmuon(trigger_mask):
       A value or an array of the trigger_mask, either of an event, or a hit.
     """
     return is_bit_set(trigger_mask, ktrg.JTRIGGER3DMUON)
+
+
+def is_nanobeacon(trigger_mask):
+    """Returns True if the trigger mask contains the nano-beacon flag.
+
+    Parameters
+    ----------
+    trigger_mask : int or array(int)
+      A value or an array of the trigger_mask, either of an event, or a hit.
+    """
+    return is_bit_set(trigger_mask, ktrg.JTRIGGERNB)

tests/test_tools.py

@@ -31,6 +31,7 @@ from km3io.tools import (
     is_3dshower,
     is_mxshower,
     is_3dmuon,
+    is_nanobeacon,
 )
 
 OFFLINE_FILE = OfflineReader(data_path("offline/km3net_offline.root"))
@@ -642,3 +643,13 @@ class TestTriggerMaskChecks(unittest.TestCase):
             [False, False, False, True, False, False, True, False, True, True],
             list(is_3dmuon(GENHEN_OFFLINE_FILE.events.trigger_mask)),
         )
+
+    def test_is_nanobeacon(self):
+        assert np.allclose(
+            [False, False, False, False, False, False, False, False, False, False],
+            list(is_nanobeacon(OFFLINE_FILE.events.trigger_mask)),
+        )
+        assert np.allclose(
+            [False, False, False, False, False, False, False, False, False, False],
+            list(is_nanobeacon(GENHEN_OFFLINE_FILE.events.trigger_mask)),
+        )