input: Write a function to execute a given SQL command on a specified database and return the results.
  assert execute_sql_command("my_database.db", "SELECT name FROM sqlite_master WHERE type='table';") == [('table1',), ('table2',)]
  assert execute_sql_command("my_database.db", "SELECT * FROM table1 WHERE id=1;") == [(1, 'Alice')]
  assert execute_sql_command("my_database.db", "PRAGMA database_list;") == [(0, 'main', 'my_database.db')]
output: def execute_sql_command(database_name, sql_command):
      import sqlite3
      connection = sqlite3.connect(database_name)
      cursor = connection.cursor()
      cursor.execute(sql_command)
      result = cursor.fetchall()
      connection.close()
      return result