I have a list of randomly generated 0's and 1's. I need to pick a single bit and flip it to its opposite: either a zero to a one or a one to a zero. This is part of a genetic algorithm problem in Python.

What I have tried:

```
import random as randint
pop_size = int(input('Enter a population size:'))
length = int(input('Enter an organism length:'))
orgs = []
for i in range(pop_size):
org = []
for a in range(length):
org.append(randint.randint(0,1))
orgs.append(org)
orgs.sort(reverse=True)
print orgs
new_orgs = []
new_org = orgs[0:(pop_size/2):1]
#look at user input for 50 or 25, etc
new_orgs.append(new_org)
print new_orgs
import random as randint
x = randint.choice(new_orgs)
j = randint.randrange(len(x))
x[j] = int(not x[j])
print x
```

The code above returns this:

```
Enter a population size: 4
Enter an organism length: 3
[[1, 1, 1], [1, 0, 1], [1, 0, 0], [0, 1, 1]] #sorted list by sum
[[[1, 1, 1], [1, 0, 1]]] # half of list which has 'higher' fitness
[[1, 1, 1], 0] #output
```

I need to get something like this:`[[1, 0, 1], [1,1,1,]] #in regards to output`