I need explanation for the code and the liberes very detailed what they are why we use them. What they do$.$ The sam for the code import dash from dash import dcc$,$ html from dash.dependencies import Input, Output import pandas as pd from geopy.geocoders import Nominatim import plotly.express as px from wordcloud import WordCloud, STOPWORDS import matplotlib.pyplot as plt # Create a map centered around the mean latitude and longitude m folium.Map$($location $=[$df$[\text{'}$Latitude$\text{'}].$ mean$),$ df$[\text{'}$Longitude$\text{'}].$mean$()],$ zoom$\_$start $=5)$ # Add markers for each location with dot size for frequency and color for place type for index, row in df$.$iterrows$()$: folium.CircleMarker$($location $=[$row$[\text{'}$Latitude$\text{'}],$ row$[\text{'}$Longitude$\text{'}]],$ radius $=5,$ # You can modify this based on the frequency color $=$ 'blue' if row$[\text{'}$Place Type'$]==$ 'Place of birth' else 'red', fill $=$ True, fill$\_$color $=$ 'blue' if row$[\text{'}$Place Type'$]$ legend html $="""$ Click on the map to filter testimonies 'Place of birth' else 'red', fill$\_$opacity$=0\mathrm{.}7,$ popup $=$ row$[\text{'}$Location$\text{'}]).$add$\_$to$($m$)$ # Add legend