docs: def read_from(self, provider, **options):
          """ All :class:`Pointer` fields in the `Sequence` read the necessary
          number of bytes from the data :class:`Provider` for their referenced
          :attr:`~Pointer.data` object. Null pointer are ignored.
  
          :param Provider provider: data :class:`Provider`.
          :keyword bool nested: if ``True`` all :class:`Pointer` fields in the
              :attr:`~Pointer.data` objects of all :class:`Pointer` fields in the
              `Sequence` reads their referenced :attr:`~Pointer.data` object as
              well (chained method call).
              Each :class:`Pointer` field stores the bytes for its referenced
              :attr:`~Pointer.data` object in its :attr:`~Pointer.bytestream`.
          """
          for item in iter(self):
              # Container or Pointer
              if is_mixin(item):
                  item.read_from(provider, **options)