It is trying to set the margin on the worksheet (if the latest version is the same as the one you are using). Without seeing any code it's not easy to say what you should do but one of these methods may be what you want

set_margins()        # Set all margins to the same value
set_margins_LR()     # Set left and right margins to the same value
set_margins_TB()     # Set top and bottom margins to the same value
set_margin_left();   # Set left margin
set_margin_right();  # Set right margin
set_margin_top();    # Set top margin
set_margin_bottom(); # Set bottom margin
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