@@ -98,10 +98,10 @@ def _backend_module_name(self, backend):
9898backend = backend .lower ()
9999
100100# Check if have specific name to module mapping.
101- backend = self ._name_to_module .get (backend ) or backend
101+ backend = self ._name_to_module .get (backend , backend )
102102
103103return (backend [9 :]if backend .startswith ("module://" )
104- else f"matplotlib.backends.backend_{ backend . lower () } )
104+ else f"matplotlib.backends.backend_{ backend } )
105105
106106def _clear (self ):
107107# Clear all dynamically-added data, used for testing only.
@@ -136,7 +136,7 @@ def _read_entry_points(self):
136136if sys .version_info >= (3 ,10 ):
137137entry_points = im .entry_points (group = group )
138138else :
139- entry_points = im .entry_points ().get (group ,{} )
139+ entry_points = im .entry_points ().get (group ,() )
140140entries = [(entry .name ,entry .value )for entry in entry_points ]
141141
142142# For backward compatibility, if matplotlib-inline and/or ipympl are installed
@@ -199,7 +199,7 @@ def backend_for_gui_framework(self, framework):
199199 """
200200return self ._GUI_FRAMEWORK_TO_BACKEND .get (framework .lower ())
201201
202- def is_valid_backend (self ,backend : str ) -> bool :
202+ def is_valid_backend (self ,backend ) :
203203"""
204204 Return True if the backend name is valid, False otherwise.
205205
@@ -262,7 +262,7 @@ def list_all(self):
262262 Backend names.
263263 """
264264self ._ensure_entry_points_loaded ()
265- return self .list_builtin ()+ list ( self ._backend_to_gui_framework . keys ())
265+ return [ * self .list_builtin (), * self ._backend_to_gui_framework ]
266266
267267def list_builtin (self ,filter_ = None ):
268268"""
@@ -286,19 +286,18 @@ def list_builtin(self, filter_=None):
286286return [k for k ,v in self ._BUILTIN_BACKEND_TO_GUI_FRAMEWORK .items ()
287287if v == "headless" ]
288288
289- return list ( self ._BUILTIN_BACKEND_TO_GUI_FRAMEWORK . keys ())
289+ return [ * self ._BUILTIN_BACKEND_TO_GUI_FRAMEWORK ]
290290
291291def list_gui_frameworks (self ):
292292"""
293- Return list ofgui frameworks used by Matplotlib backends.
293+ Return list ofGUI frameworks used by Matplotlib backends.
294294
295295 Returns
296296 -------
297297 list of str
298298 GUI framework names.
299299 """
300- return [k for k in self ._GUI_FRAMEWORK_TO_BACKEND .keys ()
301- if k != "headless" ]
300+ return [k for k in self ._GUI_FRAMEWORK_TO_BACKEND if k != "headless" ]
302301
303302def load_backend_module (self ,backend ):
304303"""
@@ -321,7 +320,7 @@ def resolve_backend(self, backend):
321320"""
322321 Return the backend and GUI framework for the specified backend name.
323322
324- If the GUI framework is not yet known then it will bedetermine by loading the
323+ If the GUI framework is not yet known then it will bedetermined by loading the
325324 backend module and checking the ``FigureCanvas.required_interactive_framework``
326325 attribute.
327326
@@ -351,8 +350,7 @@ def resolve_backend(self, backend):
351350self ._backend_to_gui_framework .get (backend ))
352351
353352# Is backend "module://something"?
354- if (gui is None and isinstance (backend ,str )and
355- backend .startswith ("module://" )):
353+ if gui is None and isinstance (backend ,str )and backend .startswith ("module://" ):
356354gui = "unknown"
357355
358356# Is backend a possible entry point?
@@ -389,7 +387,7 @@ def resolve_gui_or_backend(self, gui_or_backend):
389387
390388 Returns
391389 -------
392- Tuple ofbackend (str) and GUI framework ( str or None).
390+ tuple of (str, str or None)
393391 A non-interactive backend returns None for its GUI framework rather than
394392 "headless".
395393 """