Sample code converted from Ruby to Python:

Ruby Code:
class Point

    attr_accessor :x,y

    def initialize(x = 0, y = 0)
        @x , @y = x, y
    end

    def to_s
        str = ""
        if(@x < 0) str += "a value in is too small"
        elsif(@x > -1 && @y > -1)
            str += "x = " + @x.to_s + " y = " + @y.to_s
        else
        str = " + self.to_s + " >"
    end
end

mypoint = Point.new();


Python Code:
class Point:

    def __init__(self, x = 0, y = 0):
        self.x , self.y = x, y

    def __str__(self):
        if (self.x < 0) : 
            s = "a value in is too small"
        elif (self.x > -1 and self.y > -1):
            s = "x = " + str(self.x) + " y = " + str(self.y)
        else:
            s = "<Point " + str(self) + " >"
        return s

mypoint = Point()
# print str(mypoint)