A|B matches A or B. Put it in a group when it sits next to other pieces.

Goal

Match coastal vs highland kiosk cities.

import re
print(re.findall(r"Nairobi|Mombasa", "Nairobi Kisumu Mombasa Nakuru"))

import re
pat = r"(Nairobi|Mombasa|Kisumu)"
print(re.findall(pat, "sold in Nairobi and Kisumu"))

import re
print(re.findall(r"\b(Nakuru|Eldoret)\b", "Nakuru road to Eldoret town"))

import re
line = "city=Mombasa units=9"
print(re.search(r"city=(Nairobi|Mombasa|Kisumu)", line).group(1))