    def as_tensor(self, padding_lengths: Dict[str, int]) -> DataArray:
        """
        Given a set of specified padding lengths, actually pad the data in this field and return a
        torch Tensor (or a more complex data structure) of the correct shape.  We also take a
        couple of parameters that are important when constructing torch Tensors.

        # Parameters

        padding_lengths : `Dict[str, int]`
            This dictionary will have the same keys that were produced in
            :func:`get_padding_lengths`.  The values specify the lengths to use when padding each
            relevant dimension, aggregated across all instances in a batch.
        """
        raise NotImplementedError
Given a set of specified padding lengths, actually pad the data in this field and return a
torch Tensor (or a more complex data structure) of the correct shape.  We also take a
couple of parameters that are important when constructing torch Tensors.

# Parameters

padding_lengths : `Dict[str, int]`
This dictionary will have the same keys that were produced in
:func:`get_padding_lengths`.  The values specify the lengths to use when padding each
relevant dimension, aggregated across all instances in a batch.
allennlp/data/fields/field.py