input: Write a python function to fetch all customer requests from the 'customer_requests' table in the 'customer_requests.db' database.
  ```python
  def fetch_requests():
      con = sqlite3.connect('customer_requests.db')
      cursor = con.cursor()
      cursor.execute("SELECT request FROM customer_requests")
      results = cursor.fetchall()
      return [row[0] for row in results]
  
  # Test cases
  assert fetch_requests() == []  # Assuming the table is empty initially
  
  # Insert some test data
  con = sqlite3.connect('customer_requests.db')
  con.execute("INSERT INTO customer_requests(request) VALUES ('Request 1')")
  con.execute("INSERT INTO customer_requests(request) VALUES ('Request 2')")
  con.commit()
  
  assert fetch_requests() == ['Request 1', 'Request 2']
output: def fetch_requests():
      import sqlite3
      con = sqlite3.connect('customer_requests.db')
      cursor = con.cursor()
      cursor.execute("SELECT request FROM customer_requests")
      results = cursor.fetchall()
      con.close()
      return [row[0] for row in results]