def even_spacing(lst):
    new_lst = []  # list for the final output
    index_colon = []  # list of the indexs where ':' is found, for each line

    # find where the ':' in each line
    for line_string in lst:
        index_colon.append(line_string.find(':'))
    highest_index = max(index_colon)  # the highest index ':' can be found at in any of the lines

    # we add the extra spaces
    for index, s in enumerate(lst):
        difference = highest_index - index_colon[index]  # how many spaces will be needed


        # METHOD 1 not working, less code
        # new_lst.append(''.join(list(s).insert(index_colon[index]+1, ' '*difference)))  # insert at the index we found the proper number of spaces

        # METHOD 2, working, but more code
        list_letters = list(s)
        list_letters.insert(index_colon[index]+1, ' '*difference)
        new_lst.append(''.join(list_letters))

    return new_lst

test = ['last name: Callum', 'first name: Brian', 'middle name: Mosbey', 'balance: $0']
print even_spacing(test)