def CO_ratio(self,ifig,ixaxis):
def C_O(model):<EOL><INDENT>surface_c12=model.get('<STR_LIT>')<EOL>surface_o16=model.get('<STR_LIT>')<EOL>CORatio=old_div((surface_c12*<NUM_LIT>),(surface_o16*<NUM_LIT>))<EOL>return CORatio<EOL><DEDENT>if ixaxis=='<STR_LIT:time>':<EOL><INDENT>xax=self.get('<STR_LIT>')<EOL><DEDENT>elif ixaxis=='<STR_LIT>':<EOL><INDENT>xax=self.get('<STR_LIT>')<EOL><DEDENT>else:<EOL><INDENT>raise IOError("<STR_LIT>")<EOL><DEDENT>pl.figure(ifig)<EOL>pl.plot(xax,C_O(self))<EOL>
plot surface C/O ratio in Figure ifig with x-axis quantity ixaxis

Parameters
----------
ifig : integer
    Figure number in which to plot
ixaxis : string
    what quantity is to be on the x-axis, either 'time' or 'model'
    The default is 'model'