def to_global(s):
  """
  Format a global variable name.
  """
  if s.startswith('GPSTime'):
    s = 'Gps' + s[3:]

  if '_' in s:
    s = "".join([i.capitalize() for i in s.split("_")])
  return s[0].lower() + s[1:]
Format a global variable name.