# Buggy code
def __init__(self, parent=None):
    QPlainTextEdit.__init__(self, parent)
    BaseEditMixin.__init__(self)
    self.setAttribute(Qt.WA_DeleteOnClose)

    self.extra_selections_dict = {}

    self.textChanged.connect(self.changed)
    self.cursorPositionChanged.connect(self.cursor_position_changed)

    self.indent_chars = " " * 4
    self.tab_stop_width_spaces = 4

    # Code completion / calltips
    if parent is not None:
        mainwin = parent
        while not isinstance(mainwin, QMainWindow):
            mainwin = mainwin.parent()
            if mainwin is None:
                break
        if mainwin is not None:
            parent = mainwin

    self.completion_widget = CompletionWidget(self, parent)
    self.codecompletion_auto = False
    self.codecompletion_case = True
    self.codecompletion_enter = False
    self.setup_completion()

    self.calltip_widget = CallTipWidget(self, hide_timer_on=False)
    self.calltips = True
    self.calltip_position = None

    self.has_cell_separators = False
    self.highlight_current_cell_enabled = False

    # The color values may be overridden by the syntax highlighter
    # Highlight current line color
    self.currentline_color = QColor(Qt.red).lighter(190)
    self.currentcell_color = QColor(Qt.red).lighter(194)

    # Brace matching
    self.bracepos = None
    self.matched_p_color = QColor(Qt.green)
    self.unmatched_p_color = QColor(Qt.red)

    self.last_cursor_cell = None

    self.decorations = TextDecorationsManager(self)


# Traceback (AttributeError)
File "C:\Users\C. A. M. Gerlach\Documents\dev\SpyderDev\spyder\spyder\plugins\editor\lsp\client.py", line 230, in on_msg_received
handler(resp['result'], req_id)
File "C:\Users\C. A. M. Gerlach\Documents\dev\SpyderDev\spyder\spyder\plugins\editor\lsp\providers\document.py", line 117, in process_document_completion
LSPRequestTypes.DOCUMENT_COMPLETION, {'params': response})
File "C:\Users\C. A. M. Gerlach\Documents\dev\SpyderDev\spyder\spyder\plugins\editor\widgets\codeeditor.py", line 690, in handle_response
handler(params)
File "C:\Users\C. A. M. Gerlach\Documents\dev\SpyderDev\spyder\spyder\plugins\editor\widgets\codeeditor.py", line 790, in process_completion
self.completion_widget.show_list(completion_list, position)
File "C:\Users\C. A. M. Gerlach\Documents\dev\SpyderDev\spyder\spyder\plugins\editor\widgets\base.py", line 159, in show_list
self.update_current()
File "C:\Users\C. A. M. Gerlach\Documents\dev\SpyderDev\spyder\spyder\plugins\editor\widgets\base.py", line 222, in update_current
completion_label = completion.lower()
AttributeError: 'dict' object has no attribute 'lower'

# Fixed code
def __init__(self, parent=None):
    QPlainTextEdit.__init__(self, parent)
    BaseEditMixin.__init__(self)
    self.setAttribute(Qt.WA_DeleteOnClose)

    self.extra_selections_dict = {}

    self.textChanged.connect(self.changed)
    self.cursorPositionChanged.connect(self.cursor_position_changed)

    self.indent_chars = " " * 4
    self.tab_stop_width_spaces = 4

    # Code completion / calltips
    if parent is not None:
        mainwin = parent
        while not isinstance(mainwin, QMainWindow):
            mainwin = mainwin.parent()
            if mainwin is None:
                break
        if mainwin is not None:
            parent = mainwin

    self.completion_widget = CompletionWidget(self, parent)
    self.codecompletion_auto = False
    self.setup_completion()

    self.calltip_widget = CallTipWidget(self, hide_timer_on=False)
    self.calltip_position = None

    self.has_cell_separators = False
    self.highlight_current_cell_enabled = False

    # The color values may be overridden by the syntax highlighter
    # Highlight current line color
    self.currentline_color = QColor(Qt.red).lighter(190)
    self.currentcell_color = QColor(Qt.red).lighter(194)

    # Brace matching
    self.bracepos = None
    self.matched_p_color = QColor(Qt.green)
    self.unmatched_p_color = QColor(Qt.red)

    self.last_cursor_cell = None

    self.decorations = TextDecorationsManager(self)