Further TLObject generator clean-up

Split everything into several functions, reused some more
common code (like accessing the "real" arguments instead
constantly filtering) and more, like using classmethods
instead staticmethods and then hardcoding the class name.

telethon_generator/parsers/tlobject.py

@@ -44,6 +44,9 @@ class TLObject:
         self.class_name = snake_to_camel_case(
             self.name, suffix='Request' if self.is_function else '')
 
+        self.real_args = list(a for a in self.sorted_args() if not
+                              (a.flag_indicator or a.generic_definition))
+
     def sorted_args(self):
         """Returns the arguments properly sorted and ready to plug-in
            into a Python's method header (i.e., flags and those which
@@ -154,25 +157,7 @@ class TLArg:
 
         self.generic_definition = generic_definition
 
-    def doc_type_hint(self):
-        result = {
-            'int': 'int',
-            'long': 'int',
-            'int128': 'int',
-            'int256': 'int',
-            'string': 'str',
-            'date': 'datetime.datetime | None',  # None date = 0 timestamp
-            'bytes': 'bytes',
-            'true': 'bool',
-        }.get(self.type, self.type)
-        if self.is_vector:
-            result = 'list[{}]'.format(result)
-        if self.is_flag and self.type != 'date':
-            result += ' | None'
-
-        return result
-
-    def python_type_hint(self):
+    def type_hint(self):
         type = self.type
         if '.' in type:
             type = type.split('.')[1]