def parse_time(time, in_ms = false)
      return relative_time(time, in_ms) if time =~ /^[\-+]/
      ParseTime.new(time, in_ms).parse!
    end
def parse_time(time, in_ms = false)
      return relative_time(time, in_ms) if time =~ /^[\-+]/
      ParseTime.new(time, in_ms).parse!
    end
Return a time as an integer, however it might come in.

 @param time [Integer, String, Time] timestamp
 @param in_ms [Boolean] whether to return epoch milliseconds.
   Passing in an integer timestamp returns itself, regardless
   of this value
 @return [Integer] epoch time in seconds
 @raise Wavefront::InvalidTimestamp