code: def apply(layer: Layer, inputs: OptionalList[Tensor]) -> list[Tensor]:
      """
      Apply a layer to input[s].
  
      A flexible apply that tries to fit input to layers expected input.
      This is useful when one doesn't know if a layer expects a single tensor
      or many.
  
      :param layer: A Keras layer instance.
      :type layer: Layer
      :param inputs: A list of input tensors or a single tensor.
      :type inputs: OptionalList[Tensor]
      :return: Output from applying the layer to the input.
      :rtype: List[Tensor]
      """
  
      if isinstance(inputs, list) and len(inputs) > 1:
          try:
              ret = layer(inputs)
          except (TypeError, AttributeError) as err:
              # layer expects a single tensor.
              if len(inputs) != 1:
                  raise ValueError(
                      "Layer expects only a single input!"
                  ) from err
              ret = layer(inputs[0])
      else:
          ret = layer(inputs[0])
  
      return to_list(ret)
  
imports: from __future__ import annotations
  from typing import TypeVar
  import numpy
  import tensorflow
  import tensorflow.keras.backend
  from innvestigate.backend.types import Layer, OptionalList, ShapeTuple, Tensor
label_desc: Use image node_id 13 for calling a global function with example usage: apply(layer, inputs) and returns: to_list