Python 3.x Convert nested list of elements into nested dictionary with max recursion

I would like to convert a nested list like this:

["Pie", ["Sugar", "Biscuit", ["Egg"] ], "Cocoa", []]

to a nested dictionary like this:

{ "Pie": { "Sugar": {}, "Biscuit": { "Egg": {} } }, "Cocoa": {} }

with max recursion.

Possible variants of nested list:

["Pie", ["Sugar", "Biscuit", ["Egg"], "Something", ["Something2"] ], "Cocoa", []]

["Pie", ["Sugar", ["Biscuit"], "Another something", ["Egg"], "Something", ["Something2"] ], "Cocoa", ["One", ["Nested1"], "Two", ["Nested2"] ]]

INCORRECT variants:

["Pie", [["Sugar"], "Biscuit", ["Egg"], "Something", ["Something2"] ], "Cocoa", []]

[["Pie"], ["Sugar", "Biscuit", ["Egg"], "Something", ["Something2"] ], "Cocoa", []]

Answer

Here is one approach (see comments in the code for details):

l = ["Pie", ["Sugar", "Biscuit", ["Egg"] ], "Cocoa", []]

def to_nested(l):
    out = {}
    skip = False
    for i, e in enumerate(l):  # enumerate to keep track of position
        if skip:  # we already used this item as value, skip it
            skip = False
            continue
        # ensure we have a next item and that it is a list
        if i+1<len(l) and isinstance(l[i+1], list):
            skip = True # flag item to be skipped as key
            out[e] = to_nested(l[i+1])
        else: # add a default empty dictionary as value
            out[e] = {}
    return out

out = to_nested(l)

output:

{'Pie': {'Sugar': {}, 'Biscuit': {'Egg': {}}}, 'Cocoa': {}}