A long stretch of beach is represented by a string of two characters 0 - free, 1 - occupied. Due to recent restrictions, a new person cannot take place next to another. There has to be one free place between two people lounging on the beach. Create a function to compute how many new people at most can settle in on the given beach.
sun_loungers("10001") ➞ 1
# Can take place in the middle.
sun_loungers("00101") ➞ 1
# Can take place on the left.
sun_loungers("0") ➞ 1
# Can take one place.
sun_loungers("000") ➞ 2
# Can take places on the left and on the right.
N/A