text: VERSION = (1, 4, 3, 'final', 0)
  
  def get_version(version=None):
      """Derives a PEP386-compliant version number from VERSION."""
      if version is None:
          version = VERSION
      assert len(version) == 5
      assert version[3] in ('alpha', 'beta', 'rc', 'final')
  
      # Now build the two parts of the version number:
      # main = X.Y[.Z]
      # sub = .devN - for pre-alpha releases
      #     | {a|b|c}N - for alpha, beta and rc releases
  
      parts = 2 if version[2] == 0 else 3
      main = '.'.join(str(x) for x in version[:parts])
  
      sub = ''
      if version[3] == 'alpha' and version[4] == 0:
          # At the toplevel, this would cause an import loop.
          from django.utils.version import get_svn_revision
          svn_revision = get_svn_revision()[4:]
          if svn_revision != 'unknown':
              sub = '.dev%s' % svn_revision
  
      elif version[3] != 'final':
          mapping = {'alpha': 'a', 'beta': 'b', 'rc': 'c'}
          sub = mapping[version[3]] + str(version[4])
  
      return main + sub
  