class Features(dict):
    """A special dictionary that defines the internal structure of a dataset.

    Instantiated with a dictionary of type `dict[str, FieldType]`, where keys are the desired column names,
    and values are the type of that column.

    `FieldType` can be one of the following:
        - [`Value`] feature specifies a single data type value, e.g. `int64` or `string`.
        - [`ClassLabel`] feature specifies a predefined set of classes which can have labels associated to them and
          will be stored as integers in the dataset.
        - Python `dict` specifies a composite feature containing a mapping of sub-fields to sub-features.
          It's possible to have nested fields of nested fields in an arbitrary manner.
        - Python `list`, [`LargeList`] or [`Sequence`] specifies a composite feature containing a sequence of
          sub-features, all of the same feature type.

          <Tip>