Reorder SnapshotProvider methods in accordance with Uncle Bob

lib/tfw/components/snapshot_provider.py

@@ -31,6 +31,28 @@ class SnapshotProvider:
         if self._head_detached:
             raise EnvironmentError(f'{self.__class__.__name__} cannot init from detached HEAD state!')
 
+    @property
+    def _head_detached(self):
+        return self._branch == 'HEAD'
+
+    @property
+    def _branch(self):
+        return self._get_stdout((
+            'git', 'rev-parse',
+            '--abbrev-ref', 'HEAD'
+        ))
+
+    def _get_stdout(self, *args, **kwargs):
+        kwargs['capture_output'] = True
+        stdout_bytes = self._run(*args, **kwargs).stdout
+        return stdout_bytes.decode().rstrip('\n')
+
+    def _run(self, *args, **kwargs):
+        kwargs['check'] = True
+        if 'env' not in kwargs:
+            kwargs['env'] = self.gitenv
+        return run(*args, **kwargs)
+
     def _init_repo_if_needed(self):
         if not self._repo_is_initialized():
             self._run(('git', 'init'))
@@ -68,13 +90,6 @@ class SnapshotProvider:
         commit = self._get_commit_from_timestamp(date)
         self._checkout(commit)
 
-    def _checkout(self, what):
-        self._run((
-            'git', 'checkout',
-            what
-        ))
-        self._update_last_valid_branch()
-
     def _get_commit_from_timestamp(self, date):
         return self._get_stdout((
             'git', 'rev-list',
@@ -84,16 +99,21 @@ class SnapshotProvider:
             self._last_valid_branch
         ))
 
-    def _get_stdout(self, *args, **kwargs):
-        kwargs['capture_output'] = True
-        stdout_bytes = self._run(*args, **kwargs).stdout
-        return stdout_bytes.decode().rstrip('\n')
+    @property
+    def _last_valid_branch(self):
+        self._update_last_valid_branch()
+        return self.__last_valid_branch
 
-    def _run(self, *args, **kwargs):
-        kwargs['check'] = True
-        if 'env' not in kwargs:
-            kwargs['env'] = self.gitenv
-        return run(*args, **kwargs)
+    def _update_last_valid_branch(self):
+        if not self._head_detached:
+            self.__last_valid_branch = self._branch
+
+    def _checkout(self, what):
+        self._run((
+            'git', 'checkout',
+            what
+        ))
+        self._update_last_valid_branch()
 
     @property
     def all_timelines(self):
@@ -109,26 +129,6 @@ class SnapshotProvider:
     def timeline(self):
         return self._branch
 
-    @property
-    def _branch(self):
-        return self._get_stdout((
-            'git', 'rev-parse',
-            '--abbrev-ref', 'HEAD'
-        ))
-
-    @property
-    def _last_valid_branch(self):
-        self._update_last_valid_branch()
-        return self.__last_valid_branch
-
-    def _update_last_valid_branch(self):
-        if not self._head_detached:
-            self.__last_valid_branch = self._branch
-
-    @property
-    def _head_detached(self):
-        return self._branch == 'HEAD'
-
     @timeline.setter
     def timeline(self, value):
         self._checkout(value)