def ell_en(self,number):
        """
        Computing ellen(ln) Approximation  for a given value.
        """
        
        self.number = number

        #attempt to Approximate In for a given value        
        try:
            #Set RectangleMethod n and a fields to constant values
            #and b field to a variable value, the greater the value of n
            # the more accurate the result 
            rectangleMethod = RectangleMethod(n = 100000,a = 1, b=self.number)
        
            sum_next = 0    #Set sum_next to 0
            
            #inheriting and using midPoint function from Interval class
            #to compute ln approximation.
            for self.X_k in rectangleMethod.midPoint:
            
                self.ell_en_X = 1/self.X_k
                sum_next += self.ell_en_X
                In = (sum_next * rectangleMethod.delta_X )
                yield In
                
        #Raise TypeError if input is not numerical
        except TypeError:
            print  "\n<The entered value is not a number"

        Computing ellen(ln) Approximation  for a given value.
        
recipes/Python/576897_RectangleMethod/recipe-576897.py