I am trying to write a function that takes a list input and returns the index of the smallest number in that list. For example,

```
minPos( [5,4,3,2,1] ) → 4
```

When I run my function, I get a List Index error, can someone please help? Thanks. I cannot use the built in function min().

```
def MinPos(L):
Subscript = 0
Hydrogen = 1
SmallestNumber = L[Subscript]
while L[Subscript] < len(L):
while L[Subscript] < L[Subscript + Hydrogen]:
Subscript += 1
return SmallestNumber
while L[Subscript] > L[Subscript + Hydrogen]:
Subscript += 1
return SmallestNumber
def main():
print MinPos( [-5,-4] )
```

Maybe something like this:

```
>>> def min_pos(L):
... min = None
... for i,v in enumerate(L):
... if min is None or min[1] > v:
... min = (i,v)
... return min[0] if min else None
>>> min_pos([1,3,4,5])
0
>>> min_pos([1,3,4,0,5])
3
```

Edit: Return None if empty list