Is there tool to turn an interactive session into a script, automatically removing errors / redundant lines?

I often find myself wanting to turn an interactive session into a saved script. Usually this means manually editing the output of ipython's %hist. So for example I would paste

n_max = 10
sines = np.sin(np.arange(n_max))      #ImportError
import numpy as np
sines = np.sin(np.arange(n_max))
cosines = np.cos(np.arange(n_max))
tans = sines / cosines
tans                                  #Display values
arctans = np.arctan2(cosines / sines) #Invalid number of arguments
np.arctan2?                           #View documentation
arctans = np.arctan2(cosines, sines)
print arctans
n_max = 30                            #new value of constant
sines = np.sin(np.arange(n_max))
cosines = np.cos(np.arange(n_max))
arctans = np.arctan2(cosines, sines)
n_max = 10000                         #large number for profiling
sines = np.sin(np.arange(n_max))
cosines = np.cos(np.arange(n_max))
%timeit np.arctan2(cosines, sines)    #timing the operation
n_max = 30
sines = np.sin(np.arange(n_max))
cosines = np.cos(np.arange(n_max))
arctans = np.arctan2(cosines, sines)
print arctans

into a text editor and manually prune it down to

import numpy as np
n_max = 30
sines = np.sin(np.arange(n_max))
cosines = np.cos(np.arange(n_max))
arctans = np.arctan2(cosines, sines)
print arctans

Removing lines that gave errors, lines that defined variables that got re-defined later, etc.

My question is: is there a tool that will automate this process - look at such an input history and try to remove obviously redundant or unsuccessful lines such that the end result of running the shortened code is the same as entering the original lines one-by-one?