human
Solve the following python programming problem given the following code:
def _patch_figure_class(figure_class) : 
    def __init__(self, * args, **kwargs) : 
        super (figure_class, self).__init__ (* args, ** kwargs) 
        if ('data' not in self) : 
            self.data = GraphObjectFactory.create ('data', _parent = self, _parent_key = 'data') 
figure_class.__init__ = __init__ 
    def get_data(self, flatten = False) : 
        "
        Returns the JSON for the plot with non-data elements stripped.

        Flattening may increase the utility of the result.

        :param (bool) flatten: {'a': {'b': ''}} --> {'a.b': ''}
        :returns: (dict|list) Depending on (flat|unflat)

        " 
        return self.data.get_data (flatten = flatten) 
figure_class.get_data = get_data 
    def to_dataframe(self) : 
        '
        Create a pandas dataframe with trace names and keys as column names.

        :return: (DataFrame)

        ' 
        data = self.get_data (flatten = True) 
        from pandas import DataFrame, Series 
        return DataFrame (dict ([(k, Series (v)) for (k, v) in data.items ()])) 
figure_class.to_dataframe = to_dataframe 
    def print_grid(self) : 
        "
        Print a visual layout of the figure's axes arrangement.

        This is only valid for figures that are created
        with plotly.tools.make_subplots.

        " 
        try : 
            grid_str = self.__dict__ ['_grid_str'] 
except AttributeError : 
            raise Exception ('Use plotly.tools.make_subplots to create a subplot grid.') 
print (grid_str) 
figure_class.print_grid = print_grid 
    def append_trace(self, trace, row, col) : 
        '
        Add a data traces to your figure bound to axes at the row, col index.

        The row, col index is generated from figures created with
        plotly.tools.make_subplots and can be viewed with Figure.print_grid.

        :param (dict) trace: The data trace to be bound.
        :param (int) row: Subplot row index (see Figure.print_grid).
        :param (int) col: Subplot column index (see Figure.print_grid).

       ...

    
    

    Fix the buggy line: figure_class.append_trace = figure_class
assistant
#Here is Python code to fix the buggy line: figure_class.

figure_class.append_trace = append_trace