code: def _dynamic_init(self, only_fields, include_fields, exclude_fields):
          
  
          if not self.dynamic:
              return
  
          if (isinstance(self.request_fields, dict) and
                  self.request_fields.pop('*', None) is False):
              exclude_fields = '*'
  
          only_fields = set(only_fields or [])
          include_fields = include_fields or []
          exclude_fields = exclude_fields or []
  
          if only_fields:
              exclude_fields = '*'
              include_fields = only_fields
  
          if exclude_fields == '*':
              # First exclude all, then add back in explicitly included fields.
              include_fields = set(
                  list(include_fields) + [
                      field for field, val in six.iteritems(self.request_fields)
                      if val or val == {}
                  ]
              )
              all_fields = set(self.get_all_fields().keys())  # this is slow
              exclude_fields = all_fields - include_fields
          elif include_fields == '*':
              all_fields = set(self.get_all_fields().keys())  # this is slow
              include_fields = all_fields
  
          for name in exclude_fields:
              self.request_fields[name] = False
  
          for name in include_fields:
              if not isinstance(self.request_fields.get(name), dict):
                  # not sideloading this field
                  self.request_fields[name] = True
docs: Modifies `request_fields` via higher-level dynamic field interfaces.
  
          Arguments:
              only_fields: List of field names to render.
                  All other fields will be deferred (respects sideloads).
              include_fields: List of field names to include.
                  Adds to default field set, (respects sideloads).
                  `*` means include all fields.
              exclude_fields: List of field names to exclude.
                  Removes from default field set. If set to '*', all fields are
                  removed, except for ones that are explicitly included.