input: Write a python function to read data from a SQLite database into a Pandas DataFrame.
  assert read_data_to_df('example.db', 'table_name').equals(pd.DataFrame({'name': ['Alice', 'Bob'], 'age': [30, 25], 'gender': ['F', 'M'], 'location': ['NY', 'CA']}))
  assert read_data_to_df('example.db', 'another_table').empty
output: def read_data_to_df(db_name, table_name):
      import sqlite3
      import pandas as pd
  
      # Create a connection to the database
      conn = sqlite3.connect(db_name)
      
      # Use pandas to read the table into a DataFrame
      df = pd.read_sql_query(f"SELECT * FROM {table_name}", conn)
      
      # Close the connection
      conn.close()
      
      return df