.. index:: 
  !Extension.containsKey Method
  
.. _id3_bioseal_extension_contains_key_class_method:

===============================================================================
Extension.containsKey Method
===============================================================================

Module: :ref:`Extension<id3_bioseal_extension_class>`

Definition
----------

Determines whether the Extensionobject contains the specified key.


.. code:: Dart

    bool containsKey(String? key)

**Parameters**

.. line-block::

    ``key`` String
    :guilabel:`in` The key to locate in the  object.


**Returns**

.. line-block::

    ``bool``
    true if the  object contains an element with the specified key, otherwise false.

**Exceptions**

.. line-block::

    :ref:`BiosealException<id3_bioseal_bioseal_exception>`
    An error has occurred during Bioseal Library execution.



