[AGIPD] Split AGIPDCtrl function for clear code and adding tests later.

Based on changes in MR : https://git.xfel.eu/detectors/pycalibration/-/merge_requests/652

This MR is a preparation for the next MR for adding unit tests https://git.xfel.eu/detectors/pycalibration/-/merge_requests/646

Description

• Separate get_gain_setting() and get_acq_rate() into two different functions which read the gain_settings and acquisition rate using two different methods.

• Small refactors:

  • correct hint typing for get_gain_mode()
  • correct the doc string for get_num_cells()
  • correct the doc string for AGIPDCtrl()

How Has This Been Tested?

Relevant Documents (optional)

Types of changes

Checklist:

• I added tests where appropriate. In a separate MR: https://git.xfel.eu/detectors/pycalibration/-/merge_requests/646

Reviewers

@calibration

src/cal_tools/agipdlib.py

@@ -69,7 +69,7 @@ class AgipdCtrl:
         return options[np.argmin(dists)]
 
     def _get_acq_rate_ctrl(self) -> Optional[float]:
-        """Get acquisition (repetition) rate from RUN source."""
+        """Get acquisition (repetition) rate from CONTROL source."""
         # Attempt to look for acquisition rate in slow data
         rep_rate_src = (
             self.ctrl_src, "bunchStructure.repetitionRate.value")
@@ -115,7 +115,7 @@ class AgipdCtrl:
         return self._get_acq_rate_instr()
 
     def _get_gain_setting_ctrl(self) -> Optional[int]:
-        """Read gain_settings from RUN source and gain.value key."""
+        """Read gain_settings from CONTROL source and gain.value key."""
         return int(self.run_dc[self.ctrl_src, "gain.value"].as_single_value())
 
     def _get_gain_setting_ctrl_old(self) -> Optional[int]:
@@ -158,7 +158,7 @@ class AgipdCtrl:
         self,
         creation_time: Optional[datetime] = None,
     ) -> Optional[int]:
-        """Read Gain setting from RUN sources.
+        """Read Gain setting from CONTROL sources.
         if key `gain.value` is not available, calculate gain_setting from
         setupr and patterTypeIndex. If it failed raise ValueError.