input: Write a function to design a script in Python to scrape photos and captions from a given website. The function should take a URL as input and print the source of each photo and its caption if available. If no caption is available, it should print "No caption". The script should use BeautifulSoup and requests libraries for HTML parsing and HTTP requests respectively.
  assert generate_photo_captions('https://example.com/webpage1')==None
  assert generate_photo_captions('https://example.com/webpage2')==None
  assert generate_photo_captions('https://example.com/webpage3')==None
output: def generate_photo_captions(url):
      import requests
      from bs4 import BeautifulSoup
      
      response = requests.get(url)
      soup = BeautifulSoup(response.text, 'html.parser')
      
      for img in soup.find_all('img'):
          src = img.get('src')
          caption = img.find_next('figcaption')
          if caption:
              print(f"Photo source: {src}, Caption: {caption.text}")
          else:
              print(f"Photo source: {src}, Caption: No caption")