code: def get_hours_data(self, entries, date_headers):
          
          project_totals = get_project_totals(
              entries, date_headers, total_column=False) if entries else []
  
          data_map = {}
          for rows, totals in project_totals:
              for user, user_id, periods in rows:
                  for period in periods:
                      day = period['day']
                      if day not in data_map:
                          data_map[day] = {'billable': 0, 'nonbillable': 0}
                      data_map[day]['billable'] += period['billable']
                      data_map[day]['nonbillable'] += period['nonbillable']
  
          return data_map
docs: Sum billable and non-billable hours across all users.