code: def _compute_layer_name(is_defined_within_template, arn):
          
  
          # If the Layer is defined in the template, the arn will represent the LogicalId of the LayerVersion Resource,
          # which does not require creating a name based on the arn.
          if is_defined_within_template:
              return arn
  
          try:
              _, layer_name, layer_version = arn.rsplit(':', 2)
          except ValueError:
              raise InvalidLayerVersionArn(arn + " is an Invalid Layer Arn.")
  
          return LayerVersion.LAYER_NAME_DELIMETER.join([layer_name,
                                                         layer_version,
                                                         hashlib.sha256(arn.encode('utf-8')).hexdigest()[0:10]])
docs: Computes a unique name based on the LayerVersion Arn
  
          Format:
          <Name of the LayerVersion>-<Version of the LayerVersion>-<sha256 of the arn>
  
          Parameters
          ----------
          is_defined_within_template bool
              True if the resource is a Ref to a resource otherwise False
          arn str
              ARN of the Resource
  
          Returns
          -------
          str
              A unique name that represents the LayerVersion