code: def parsehours (hrstr):
      
      hr = _parsesexagesimal (hrstr, 'hours', False)
      if hr >= 24:
          raise ValueError ('illegal hour specification: ' + hrstr)
      return hr * H2R
docs: Parse a string formatted as sexagesimal hours into an angle.
  
      This function converts a textual representation of an angle, measured in
      hours, into a floating point value measured in radians. The format of
      *hrstr* is very limited: it may not have leading or trailing whitespace,
      and the components of the sexagesimal representation must be separated by
      colons. The input must therefore resemble something like
      ``"12:34:56.78"``. A :exc:`ValueError` will be raised if the input does
      not resemble this template. Hours greater than 24 are not allowed, but
      negative values are.