Parse a human readable string of a byte string.

    Args:
      string: The string to parse.

    Raises:
      DecodeError: If the string can not be parsed.

def ParseFromHumanReadable(self, string):
    """Parse a human readable string of a byte string.

    Args:
      string: The string to parse.

    Raises:
      DecodeError: If the string can not be parsed.
    """
    if not string:
      return None

    match = self.REGEX.match(string.strip().lower())
    if not match:
      raise DecodeError("Unknown specification for ByteSize %s" % string)

    multiplier = self.DIVIDERS.get(match.group(2))
    if not multiplier:
      raise DecodeError("Invalid multiplier %s" % match.group(2))

    # The value may be represented as a float, but if not dont lose accuracy.
    value = match.group(1)
    if "." in value:
      value = float(value)
    else:
      value = int(value)

    self._value = int(value * multiplier)