code: def add_quota(self, quota):
          
          if quota.limit in (None, -1, float('inf')):
              # Handle "unlimited" quotas.
              self.usages[quota.name]['quota'] = float("inf")
              self.usages[quota.name]['available'] = float("inf")
          else:
              self.usages[quota.name]['quota'] = int(quota.limit)
docs: Adds an internal tracking reference for the given quota.