<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:

def destroy_vm_vdis(name=None, session=None, call=None):
    '''
    Get virtual block devices on VM

    .. code-block:: bash

        salt-cloud -a destroy_vm_vdis  xenvm01

    '''
    if session is None:
        session = _get_session()
    ret = {}
    # get vm object
    vms = session.xenapi.VM.get_by_name_label(name)
    if len(vms) == 1:
        # read virtual block device (vdb)
        vbds = session.xenapi.VM.get_VBDs(vms[0])
        if vbds is not None:
            x = 0
            for vbd in vbds:
                vbd_record = session.xenapi.VBD.get_record(vbd)
                if vbd_record['VDI'] != 'OpaqueRef:NULL':
                    # read vdi on vdb
                    vdi_record = session.xenapi.VDI.get_record(
                        vbd_record['VDI'])
                    if 'iso' not in vdi_record['name_label']:
                        session.xenapi.VDI.destroy(vbd_record['VDI'])
                        ret['vdi-{}'.format(x)] = vdi_record['name_label']
                x += 1
    return ret