code: def versions_from_trove(trove):
      
      versions = set()
      for classifier in trove:
          if 'Programming Language :: Python ::' in classifier:
              ver = classifier.split('::')[-1]
              major = ver.split('.')[0].strip()
              if major:
                  versions.add(major)
      return sorted(
          set([v for v in versions if v.replace('.', '', 1).isdigit()]))
docs: Finds out python version from list of trove classifiers.
      Args:
          trove: list of trove classifiers
      Returns:
          python version string