Replace weird mixin Client classes with free-standing defs

This should take care of the extremely precarious subclassing order.
It should also make IDEs go a lot less crazy.
Documentation and code can be kept separated.

telethon/client/buttons.py

@@ -4,93 +4,62 @@ from .. import utils, hints
 from ..tl import types, custom
 
 
-class ButtonMethods:
-    @staticmethod
-    def build_reply_markup(
-            buttons: 'typing.Optional[hints.MarkupLike]',
-            inline_only: bool = False) -> 'typing.Optional[types.TypeReplyMarkup]':
-        """
-        Builds a :tl:`ReplyInlineMarkup` or :tl:`ReplyKeyboardMarkup` for
-        the given buttons.
+def build_reply_markup(
+        buttons: 'typing.Optional[hints.MarkupLike]',
+        inline_only: bool = False) -> 'typing.Optional[types.TypeReplyMarkup]':
+    if buttons is None:
+        return None
 
-        Does nothing if either no buttons are provided or the provided
-        argument is already a reply markup.
+    try:
+        if buttons.SUBCLASS_OF_ID == 0xe2e10ef2:
+            return buttons  # crc32(b'ReplyMarkup'):
+    except AttributeError:
+        pass
 
-        You should consider using this method if you are going to reuse
-        the markup very often. Otherwise, it is not necessary.
+    if not utils.is_list_like(buttons):
+        buttons = [[buttons]]
+    elif not buttons or not utils.is_list_like(buttons[0]):
+        buttons = [buttons]
 
-        This method is **not** asynchronous (don't use ``await`` on it).
+    is_inline = False
+    is_normal = False
+    resize = None
+    single_use = None
+    selective = None
 
-        Arguments
-            buttons (`hints.MarkupLike`):
-                The button, list of buttons, array of buttons or markup
-                to convert into a markup.
+    rows = []
+    for row in buttons:
+        current = []
+        for button in row:
+            if isinstance(button, custom.Button):
+                if button.resize is not None:
+                    resize = button.resize
+                if button.single_use is not None:
+                    single_use = button.single_use
+                if button.selective is not None:
+                    selective = button.selective
 
-            inline_only (`bool`, optional):
-                Whether the buttons **must** be inline buttons only or not.
+                button = button.button
+            elif isinstance(button, custom.MessageButton):
+                button = button.button
 
-        Example
-            .. code-block:: python
+            inline = custom.Button._is_inline(button)
+            is_inline |= inline
+            is_normal |= not inline
 
-                from telethon import Button
+            if button.SUBCLASS_OF_ID == 0xbad74a3:
+                # 0xbad74a3 == crc32(b'KeyboardButton')
+                current.append(button)
 
-                markup = client.build_reply_markup(Button.inline('hi'))
-                # later
-                await client.send_message(chat, 'click me', buttons=markup)
-        """
-        if buttons is None:
-            return None
+        if current:
+            rows.append(types.KeyboardButtonRow(current))
 
-        try:
-            if buttons.SUBCLASS_OF_ID == 0xe2e10ef2:
-                return buttons  # crc32(b'ReplyMarkup'):
-        except AttributeError:
-            pass
-
-        if not utils.is_list_like(buttons):
-            buttons = [[buttons]]
-        elif not buttons or not utils.is_list_like(buttons[0]):
-            buttons = [buttons]
-
-        is_inline = False
-        is_normal = False
-        resize = None
-        single_use = None
-        selective = None
-
-        rows = []
-        for row in buttons:
-            current = []
-            for button in row:
-                if isinstance(button, custom.Button):
-                    if button.resize is not None:
-                        resize = button.resize
-                    if button.single_use is not None:
-                        single_use = button.single_use
-                    if button.selective is not None:
-                        selective = button.selective
-
-                    button = button.button
-                elif isinstance(button, custom.MessageButton):
-                    button = button.button
-
-                inline = custom.Button._is_inline(button)
-                is_inline |= inline
-                is_normal |= not inline
-
-                if button.SUBCLASS_OF_ID == 0xbad74a3:
-                    # 0xbad74a3 == crc32(b'KeyboardButton')
-                    current.append(button)
-
-            if current:
-                rows.append(types.KeyboardButtonRow(current))
-
-        if inline_only and is_normal:
-            raise ValueError('You cannot use non-inline buttons here')
-        elif is_inline == is_normal and is_normal:
-            raise ValueError('You cannot mix inline with normal buttons')
-        elif is_inline:
-            return types.ReplyInlineMarkup(rows)
-        # elif is_normal:
-        return types.ReplyKeyboardMarkup(
-            rows, resize=resize, single_use=single_use, selective=selective)
+    if inline_only and is_normal:
+        raise ValueError('You cannot use non-inline buttons here')
+    elif is_inline == is_normal and is_normal:
+        raise ValueError('You cannot mix inline with normal buttons')
+    elif is_inline:
+        return types.ReplyInlineMarkup(rows)
+    # elif is_normal:
+    return types.ReplyKeyboardMarkup(
+        rows, resize=resize, single_use=single_use, selective=selective)