Callback error with multiple multi-dropdowns

Hello guys,
I am getting call back errors while generating graph for the below table. I want the Country, State, City and Restaurants to be the multi-dropdown filters and year slider for the x-axis. I want to plot a bar chart of sales and total quantity. below is my code. Please ignore the scatter plot I have mentioned in the code. I would really appreciate any help as it is pretty urgent. Thanks in advance.

my code:

import dash
import dash_core_components as dcc
import dash_html_components as html
from dash.dependencies import Input, Output

import pandas as pd
import plotly.graph_objs as go

external_stylesheets = [‘https://codepen.io/chriddyp/pen/bWLwgP.css’]

app = dash.Dash(name, external_stylesheets=external_stylesheets)

df = pd.read_csv(r’Desktop\testBook4.csv’)

COU = df[‘Country’].unique()
STA = df[‘State’].unique()
CIT = df[‘City’].unique()
RES = df[‘Restaurants’].unique()

app.layout = html.Div([
html.Div([

    html.Div([
        dcc.Dropdown(
            id='dd1',
			multi=True,
            options=[{'label': i, 'value': i} for i in COU],
            value='USA'
        ),
        
    ],
    style={'width': '20%', 'display': 'inline-block'}),

    html.Div([
        dcc.Dropdown(
            id='dd2',
            multi=True,
			options=[{'label': i, 'value': i} for i in STA],
            value='NJ'
        ),
        
    ],
    style={'width': '20%', 'display': 'inline-block'}),

	html.Div([
        dcc.Dropdown(
            id='dd3',
            multi=True,
			options=[{'label': i, 'value': i} for i in CIT],
            value='jersey city'
        ),
        
    ],
    style={'width': '20%', 'display': 'inline-block'}),

	
	html.Div([
        dcc.Dropdown(
            id='dd4',
            multi=True,
			options=[{'label': i, 'value': i} for i in ag],
            value='bww'
        ),
        
    ],style={'width': '20%', 'float': 'right', 'display': 'inline-block'})
]),

dcc.Graph(id='indicator-graphic'),

dcc.Slider(
    id='year--slider',
    min=df['Year'].min(),
    max=df['Year'].max(),
    value=df['Year'].max(),
    marks={str(year): str(year) for year in df['Year'].unique()},
    step=None
)

])

@app.callback(
Output(‘indicator-graphic’, ‘figure’),
[Input(‘year–slider’, ‘value’)])
def update_figure(selected_year):
filtered_df = df[df.Year == selected_year]
traces = []
for i in filtered_df.BG.unique():
df_by_COU = filtered_df[filtered_df[‘Country’] == i]
traces.append(go.Scatter(
x=df_by_COU[‘Total Quantity’],
y=df_by_COU[‘Sales’],
mode=‘markers’,
opacity=0.7,
marker={
‘size’: 15,
‘line’: {‘width’: 0.5, ‘color’: ‘white’}
},
name=i
))

for j in filtered_df.State.unique():
    df_by_STA = filtered_df[filtered_df['State'] == j]
    traces.append(go.Scatter(
        x=df_by_STA['Total Quantity'],
        y=df_by_STA['Sales to Thirds'],
        mode='markers',
        opacity=0.7,
        marker={
        'size': 15,
        'line': {'width': 0.5, 'color': 'white'}
        },
        name=j 

return {
    'data': traces,
    'layout': go.Layout(
        xaxis={'type': 'log', 'title': 'X'},
        yaxis={'title': 'Y', 'range': [20, 90]},
        margin={'l': 40, 'b': 40, 't': 10, 'r': 10},
        legend={'x': 0, 'y': 1},
        hovermode='closest'
    )
}

if name == ‘main’:
app.run_server(debug=True)