syntax error when doing try-except with the except command

edit

I am running sage via virtual box and for some reason I am getting a syntax error for except. I was wondering if this wasn't available because I am using virtual box or if I am doing something wrong.

example below,

sage: def total_chromatic_number(G, certificate=False):
....:     nmax = len(G) + len(G.edges()) # trivial upper bound on the number of colors.
....:     for n in range(1,nmax+1):
....:         p = MixedIntegerLinearProgram()
....:         bv = p.new_variable(binary=True)
....:         be = p.new_variable(binary=True)
....:         for v in G.vertices():
....:             p.add_constraint(sum(bv[v,c] for c in range(n)) == 1)
....:         for e in G.edges(labels=False):
....:             p.add_constraint(sum(be[e,c] for c in range(n)) == 1)
....:         for v in G.vertices():
....:             for c in range(n):
....:                 p.add_constraint(bv[v,c] + sum(be[e,c] for e in G.edges_incident(v, labels=False)) <= 1)
....:         for v,w in G.edges(labels=False):
....:             for c in range(n):
....:                 p.add_constraint(bv[v,c] + bv[w,c] + be[(v,w),c] <= 1)
....:         try:    
....:             p.solve()
....:             if certificate:
....:                 bv_sol = p.get_values(bv)
....:                 be_sol = p.get_values(be)
....:                 coloration = {}
....:                 for v in G.vertices():
....:                     for c in range(n):
....:                         if bv_sol[v,c] == 1:
....:                             coloration[v] = c
....:                 for e in G.edges(labels=False):
....:                     for c in range(n):
....:                         if be_sol[e,c] == 1:
....:                             coloration[e] = c
....:                 return coloration
....:             else:
....:                 return n
....:         except MIPSolverException:

   File "<ipython-input-17-059a0ac5e5a6>", line 34
     except  MIPSolverException:
          ^
SyntaxError: invalid syntax