function unblock (options) {
  if (is.object(options)) {
    if (Array.isArray(options.operation) && options.operation.every(is.string)) {
      sharp.block(options.operation, false);
    } else {
      throw is.invalidParameterError('operation', 'Array<string>', options.operation);
    }
  } else {
    throw is.invalidParameterError('options', 'object', options);
  }
}
Unblock libvips operations at runtime.

This is useful for defining a list of allowed operations.

@since 0.32.4

@example <caption>Block all input except WebP from the filesystem.</caption>
sharp.block({
  operation: ['VipsForeignLoad']
});
sharp.unblock({
  operation: ['VipsForeignLoadWebpFile']
});

@example <caption>Block all input except JPEG and PNG from a Buffer or Stream.</caption>
sharp.block({
  operation: ['VipsForeignLoad']
});
sharp.unblock({
  operation: ['VipsForeignLoadJpegBuffer', 'VipsForeignLoadPngBuffer']
});

@param {Object} options
@param {Array<string>} options.operation - List of libvips low-level operation names to unblock.