human
Complete this python program:
def iter_blocks(course):
assistant
#Here is the Python code you requested.

    """Returns an iterator over all of the blocks in a course.
    """
    def visit(block):
        '    get    child    blocks    '
        (yield block)
        for child in block.get_children():
            for descendant in visit(child):
                (yield descendant)
    return visit(course)