def two_lists_get_intersect(l1,l2):
    """
    Given two lists, return list with common elements.

    >>> l1 = [1,5,10,20,30]
    >>> l2 = [5,20,40]
    >>> two_lists_get_intersect(l1, l2)
    [5, 20]
    >>> l3 = [50]
    >>> two_lists_get_intersect(l1, l3)
    []

    """

    assert l1, "given l1 empty"
    assert l2, "given l2 empty"
    l3 = [element for element in l1 if element in l2]
    return l3