Plotly type error multiple values for arguement

Question

I need help with the following code. I'm playing around with Plotly and i'm trying to create a line graph for the sales vs the year. Below is the code:

# set up environment
from dash import Dash, dcc, html, Output, Input
import plotly.graph_objs as go
import pandas as pd
import numpy as np
import plotly.express as px

# app set up
app = Dash(__name__)

# load and clean dataset
df = pd.read_csv('sales_data_sample.csv', encoding = 'Latin-1')
df = df.drop(['ADDRESSLINE2', 'STATE', 'POSTALCODE', 'TERRITORY'], axis = 1) # remove nulls
df.columns = df.columns.str.lower() # lower the column names to make it easier to type

# draw line graph
fig = go.Figure(data=[go.Scatter(x = df['year_id'], y = df['sales'])])

# layout
app.layout = html.Div([
    html.Div([
        
        html.Div(children = [
            html.H1('Sales Snapshot'),

            html.Div(children = '''
            Summary information from sample Dataset
            ''')
            ], style = {'textAlign': 'center', 'marginTop': 40, 'marginBottom': 40}),

            html.Div([
                dcc.Dropdown(
                    [df['productline'].unique()],  id = 'product-dropdown-1'),
                    html.Div(id = 'dd-output-container')
            ]),
            
            html.Div([
                dcc.Graph(
                    figure = fig,
                    id = 'line-container'
            )
        ])            
    ])
])

@app.callback(
    Output('dd-output-container', 'children'),
    Input('product-dropdown-1', 'value')
)
def update_output(value):
    return f'You have selected {value}'


# app run
if __name__ == '__main__':
    app.run_server(debug = True)

I keep getting this error:

TypeError: init() got multiple values for argument 'id'

I can't figure out where the problem is. I don't know why its getting multiple values for id, i'm assigning the argument that plotly is asking for.