Fix irf tool for only proton file; remove refs to visualization code …

…in docs

docs/api-reference/irf/index.rst

@@ -22,9 +22,6 @@ are done using the `pyirf <https://pyirf.readthedocs.io/en/stable/>`_ package.
 :ref:`binning`, :ref:`preprocessing`, and :ref:`spectra` contain helper functions and classes used by many of the
 other components in this module.
 
-:ref:`irf_visualization` and :ref:`vis_utils` implement some functionalities for visualizing
-the irf components.
-
 
 Submodules
 ==========
@@ -38,8 +35,6 @@ Submodules
     binning
     preprocessing
     spectra
-    visualization
-    vis_utils
 
 
 Reference/API

src/ctapipe/tools/make_irf.py

@@ -354,7 +354,7 @@ def calculate_selections(self, reduced_events: dict) -> dict:
                     self.opt_result.gh_cuts,
                     operator.ge,
                 )
-                n_sel["bg_type"] = np.count_nonzero(
+                n_sel[bg_type] = np.count_nonzero(
                     reduced_events[bg_type]["selected_gh"]
                 )