code: def get_block_overview(block_representation, coin_symbol='btc', txn_limit=None,
          txn_offset=None, api_key=None):
      
  
      assert is_valid_coin_symbol(coin_symbol)
      assert is_valid_block_representation(
              block_representation=block_representation,
              coin_symbol=coin_symbol)
  
      url = make_url(coin_symbol, **dict(blocks=block_representation))
  
      params = {}
      if api_key:
          params['token'] = api_key
      if txn_limit:
          params['limit'] = txn_limit
      if txn_offset:
          params['txstart'] = txn_offset
  
      r = requests.get(url, params=params, verify=True, timeout=TIMEOUT_IN_SECONDS)
      response_dict = get_valid_json(r)
  
      if 'error' in response_dict:
          return response_dict
      return _clean_block(response_dict=response_dict)
docs: Takes a block_representation, coin_symbol and txn_limit and gets an overview
      of that block, including up to X transaction ids.
      Note that block_representation may be the block number or block hash