input: def fetch_and_return_json() -> str:
      """
      Develops an API in Python that fetches data from an SQL database and presents the data in the form of a JSON. 
      This function fetches all users from the 'users' table in 'database.db' and returns the data as a JSON 
      string.
      >>> fetch_and_return_json()
      '[{"id": 1, "name": "John Doe"}, {"id": 2, "name": "Jane Smith"}]'
      """
output:     import sqlite3
      import json
  
      conn = sqlite3.connect('database.db')
      cursor = conn.cursor()
      cursor.execute("SELECT id, name FROM users")
      rows = cursor.fetchall()
      conn.close()
  
      users = [{"id": row[0], "name": row[1]} for row in rows]
      return json.dumps(users)