input: def fetch_sql_data_as_json() -> str:
      """Returns a JSON representation of the 'users' table from the 'database.db' SQLite database by using a Flask API.
      >>> fetch_sql_data_as_json() # Output depends on the 'users' table content in 'database.db'
      '{"user1": {"name": "John", "email": "john@example.com"}, "user2": {"name": "Jane", "email": "jane@example.com"}}'
      """
      import json 
      import sqlite3
      from flask import Flask, request, jsonify 
  
      app = Flask(__name__) 
      
      def dict_factory(cursor, row):
          d = {}
          for idx, col in enumerate(cursor.description):
              d[col[0]] = row[idx]
          return d 
      
      @app.route('/', methods=['GET'])
      def index(): 
          connection = sqlite3.connect('database.db')
          connection.row_factory = dict_factory
          cur = connection.cursor() 
          all_users = cur.execute('SELECT * FROM users;').fetchall() 
          return jsonify(all_users) 
      
      if __name__ == '__main__': 
          app.run(debug = True)
output:     with app.test_client() as client:
          response = client.get('/')
          return response.get_data(as_text=True)