Default to None rather than empty string

src/genie_python/genie.py

@@ -859,9 +859,9 @@ def connected_pvs_in_list(pv_list: list[str], is_local: bool = False) -> list[st
 def begin(
     period: int = 1,
     meas_id: str | None = None,
-    meas_type: str = "",
-    meas_subid: str = "",
-    sample_id: str = "",
+    meas_type: str | None = None,
+    meas_subid: str | None = None,
+    sample_id: str | None = None,
     delayed: bool = False,
     quiet: bool = False,
     paused: bool = False,

src/genie_python/genie_epics_api.py

@@ -77,6 +77,8 @@ def __init__(
         self.motion_suffix = "CS:MOT:MOVING"
         self.pre_post_cmd_manager = PrePostCmdManager()
         self.logger = GenieLogger()
+        self._sample_par_names_cache = None
+        self._beamline_par_names_cache = None
 
         if environment_details is None:
             self._environment_details = EnvironmentDetails()
@@ -680,19 +682,21 @@ def set_sample_par(self, name: str, value: "PVValue") -> None:
             name: the name of the parameter to change
             value: the new value
         """
+
         assert self.blockserver is not None
-        names = self.blockserver.get_sample_par_names()
-        if (
-            names is not None
-            and isinstance(names, list)
-            and all(isinstance(elem, str) for elem in names)
-        ):
+        try:
+            names = self.blockserver.get_sample_par_names()
+            self._sample_par_names_cache = names
+        except Exception:
+            names = self._sample_par_names_cache
+        if names is not None and isinstance(names, list):
             for n in names:
-                m = re.match(".+:SAMPLE:%s" % name.upper(), n)
-                if m is not None:
-                    # Found it!
-                    self.set_pv_value(self.prefix_pv_name(n), value)
-                    return
+                if isinstance(n, str):
+                    m = re.match(".+:SAMPLE:%s" % name.upper(), n)
+                    if m is not None:
+                        # Found it!
+                        self.set_pv_value(self.prefix_pv_name(n), value)
+                        return
         raise Exception("Sample parameter %s does not exist" % name)
 
     def get_beamline_pars(self) -> "_GetbeamlineparsReturn":
@@ -712,8 +716,14 @@ def set_beamline_par(self, name: str, value: "PVValue") -> None:
             name: the name of the parameter to change
             value: the new value
         """
+
         assert self.blockserver is not None
-        names = self.blockserver.get_beamline_par_names()
+        try:
+            names = self.blockserver.get_beamline_par_names()
+            self._beamline_par_names_cache = names
+        except Exception:
+            names = self._beamline_par_names_cache
+
         if names is not None:
             for n in names:
                 m = re.match(".+:BL:%s" % name.upper(), n)