orelevance = {'Medium 6': '0.6'}

s = orelevance.values()
a = float([x for x in s][0])
cost = 1000
print(a*cost)
Basically what this does is it takes a dictionary, converts the value to a float and multiplies it by the cost.
In Odoo I have an item in the inventory that has a cost which i believe is the field standard_price,
and I want to take that cost and multiply it by a selection in a drop down list. Hence converting the dictionary into a float. 
The result would then get stored in a new list_price field. 

Can anyone help with this. I can explain it some more if my question isn't totally clear.