Return the VM's size object

def get_size(conn, vm_):
    '''
    Return the VM's size object
    '''
    sizes = conn.list_sizes()
    vm_size = config.get_cloud_config_value('size', vm_, __opts__)
    if not vm_size:
        return sizes[0]

    for size in sizes:
        if vm_size and six.text_type(vm_size) in (six.text_type(sizes[size]['id']), six.text_type(size)):
            return sizes[size]['id']
    raise SaltCloudNotFound(
        'The specified size, \'{0}\', could not be found.'.format(vm_size)
    )