input: Write a python function to get all documents from a Firebase collection.
  assert get_all_docs("https://example.firebaseio.com", "users") is not None
  assert get_all_docs("https://example.firebaseio.com", "products") == {"product1": {"name": "Laptop", "price": 1000}, "product2": {"name": "Phone", "price": 500}}
  assert isinstance(get_all_docs("https://example.firebaseio.com", "orders"), dict)
output: import requests
  
  def get_all_docs(base_url, collection):
      url = f"{base_url}/{collection}.json"
      response = requests.get(url)
      if response.status_code == 200:
          return response.json()
      else:
          return None