create dictionary of cities

series_dict.py

# Create list of cities
cities_list = list(population['City,State'])

# group cities from the population_melt.csv
def rnd_series(city):
    subset = population_melt[population_melt['City,State']== city]
    dates = (pd.DataFrame({'ds': pd.to_datetime(population_melt['ds'])}))
    return subset

# create dictionary of city name and grouped population_melt.csv
series = [rnd_series(city) for city in cities_list]