Add some comments

safe_transaction_service/history/services/balance_service.py

@@ -173,7 +173,14 @@ def get_balances(
  django_cache.set(cache_key_count, count, 60 * 10) # 10 minutes cache
  return balances, count
 
- def _get_erc20_limits(self, limit, offset) -> Tuple[int, int]:
+ def _get_erc20_list_limits(self, limit: int, offset: int) -> Tuple[int, int]:
+ """
+ Calculates the number of elements that must be taken from ERC20 list and return the start and end limits.
+
+ :param limit:
+ :param offset:
+ :return: Tuple start, end
+ """
  if not limit:
  # No pagination no limits
  return 0, None
@@ -241,6 +248,7 @@ def _get_balances(
 
  balances = []
  if offset != 0 and raw_balances:
+ # Remove ethereum balance if is not the first page
  raw_balances = raw_balances[1:]
 
  for balance in raw_balances: