docs: def create_new_sub_account(self, account_id, account_name, account_default_group_storage_quota_mb=None, account_default_storage_quota_mb=None, account_default_user_storage_quota_mb=None, account_sis_account_id=None):
          """
          Create a new sub-account.
  
          Add a new sub-account to a given account.
          """
          path = {}
          data = {}
          params = {}
  
          # REQUIRED - PATH - account_id
          """ID"""
          path["account_id"] = account_id
  
          # REQUIRED - account[name]
          """The name of the new sub-account."""
          data["account[name]"] = account_name
  
          # OPTIONAL - account[sis_account_id]
          """The account's identifier in the Student Information System."""
          if account_sis_account_id is not None:
              data["account[sis_account_id]"] = account_sis_account_id
  
          # OPTIONAL - account[default_storage_quota_mb]
          """The default course storage quota to be used, if not otherwise specified."""
          if account_default_storage_quota_mb is not None:
              data["account[default_storage_quota_mb]"] = account_default_storage_quota_mb
  
          # OPTIONAL - account[default_user_storage_quota_mb]
          """The default user storage quota to be used, if not otherwise specified."""
          if account_default_user_storage_quota_mb is not None:
              data["account[default_user_storage_quota_mb]"] = account_default_user_storage_quota_mb
  
          # OPTIONAL - account[default_group_storage_quota_mb]
          """The default group storage quota to be used, if not otherwise specified."""
          if account_default_group_storage_quota_mb is not None:
              data["account[default_group_storage_quota_mb]"] = account_default_group_storage_quota_mb
  
          self.logger.debug("POST /api/v1/accounts/{account_id}/sub_accounts with query params: {params} and form data: {data}".format(params=params, data=data, **path))
          return self.generic_request("POST", "/api/v1/accounts/{account_id}/sub_accounts".format(**path), data=data, params=params, single_item=True)