gistfile1.py

class Comparable(object):
  def __init__(self, name):
    self.name = name
    self.is_neg = False

  def __neg__(self):
    self.is_neg = not self.is_neg
    return self

  def op(self, op, value):
    try:
      float(value)
      return "{}{}.{}:{}".format(
        "not " if self.is_neg else "",
        self.name,
        op,
        value
      )
    except:
      raise ValueError(value)

  def __eq__(self, value):
    return self.op("eq", value)

  def __gt__(self, value):
    return self.op("gt", value)

  def __lt__(self, value):
    return self.op("lt", value)

  def __ge__(self, value):
    return self.op("gte", value)

  def __le__(self, value):
    return self.op("lte", value)