docs: def Versions():
      """Returns a string with version information.
  
      You would call this function if you want a string giving detailed information
      on the version of ``phydms`` and the associated packages that it uses.
      """
      s = [\
              'Version information:',
              '\tTime and date: %s' % time.asctime(),
              '\tPlatform: %s' % platform.platform(),
              '\tPython version: %s' % sys.version.replace('\n', ' '),
              '\tphydms version: %s' % phydmslib.__version__,
              ]
      for modname in ['Bio', 'cython', 'numpy', 'scipy', 'matplotlib',
              'natsort', 'sympy', 'six', 'pandas', 'pyvolve', 'statsmodels',
              'weblogolib', 'PyPDF2']:
          try:
              v = importlib.import_module(modname).__version__
              s.append('\t%s version: %s' % (modname, v))
          except ImportError:
              s.append('\t%s cannot be imported into Python' % modname)
      return '\n'.join(s)