code: def git_day():
      
      vec = ['env', 'TZ=UTC', 'git', 'log', '--date=iso-local', '--pretty=%ad']
      day = cmd(*(vec + ['-n', '1'])).split()[0]
      commits = cmd(*(vec + ['--since', day + 'T00:00Z'])).strip()
      n = len(commits.split('\n'))
      day = day.replace('-', '')
      if n > 1:
          day += '.%s' % n
      # Branches that are not master are treated as local:
      #   https://www.python.org/dev/peps/pep-0440/#local-version-identifiers
      branch = get_git_branch()
      if branch != 'master':
          day += '+' + s(branch)
      return day
docs: Constructs a version string of the form:
  
             day[.<commit-number-in-day>][+<branch-name-if-not-master>]
  
         Master is understood to be always buildable and thus untagged
         versions are treated as patch levels. Branches not master are treated
         as PEP-440 "local version identifiers".