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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:

def get_default_keychain(user=None, domain="user"):
    '''
    Get the default keychain

    user
        The user to check the default keychain of

    domain
        The domain to use valid values are user|system|common|dynamic, the default is user

    CLI Example:

    .. code-block:: bash

        salt '*' keychain.get_default_keychain
    '''
    cmd = "security default-keychain -d {0}".format(domain)
    return __salt__['cmd.run'](cmd, runas=user)