alpine package py-pip missing

Problem

Im trying to install python pip in my alpine using Docker compose file but get the following error.

ERROR: unsatisfiable constraints:
  py-pip (missing):
    required by: world[py-pip]
ERROR: Service 'web' failed to build: The command '/bin/sh -c apk add py-pip' returned a non-zero code: 1

Solution and Answer

Do update first:

apk add --update py-pip

Or:

apk update
apk add py-pip