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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 define_vol_xml_str(xml, **kwargs):  # pylint: disable=redefined-outer-name
    '''
    Define a volume based on the XML passed to the function

    :param xml: libvirt XML definition of the storage volume
    :param connection: libvirt connection URI, overriding defaults

        .. versionadded:: 2019.2.0
    :param username: username to connect with, overriding defaults

        .. versionadded:: 2019.2.0
    :param password: password to connect with, overriding defaults

        .. versionadded:: 2019.2.0

    CLI Example:

    .. code-block:: bash

        salt '*' virt.define_vol_xml_str <XML in string format>

    The storage pool where the disk image will be defined is ``default``
    unless changed with a configuration like this:

    .. code-block:: yaml

        virt:
            storagepool: mine
    '''
    poolname = __salt__['config.get']('libvirt:storagepool', None)
    if poolname is not None:
        salt.utils.versions.warn_until(
            'Sodium',
            '\'libvirt:storagepool\' has been deprecated in favor of '
            '\'virt:storagepool\'. \'libvirt:storagepool\' will stop '
            'being used in {version}.'
        )
    else:
        poolname = __salt__['config.get']('virt:storagepool', 'default')

    conn = __get_conn(**kwargs)
    pool = conn.storagePoolLookupByName(six.text_type(poolname))
    ret = pool.createXML(xml, 0) is not None
    conn.close()
    return ret