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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def updateratio(ctx, symbol, ratio, account):
 """ Update the collateral ratio of a call positions """

    from bitshares.dex import Dex

    dex = Dex(bitshares_instance=ctx.bitshares)
    print_tx(dex.adjust_collateral_ratio(symbol, ratio, account=account))