<pre><code>import copy
class Polynomial(dict):
def __init__(self, coefficients):
self.coeff = coefficients
def dictionary(self,x):
sum=0.0
d=self.coeff
for k in d:
sum +=d[k]*x**k
return sum
def __add__(self, other):
new=copy.deepcopy(self)
for k,d in other.coeff:
if k in new:
new[k] +=value
else:
new[k]=value
return Polynomial(new)
p = Polynomial({20:1,1:-1,100:4})
q = Polynomial({1:1,100:-3})
print q+q
</code></pre>