def leftEndPoint(self):
        """
        Compute the value of Xk of each point using the
        left endpoint of each subinterval
        """
        
        # Start with an empty list
        left_list = []

        #attempt to create a list of Xk points using the left endpoint
        try:
            for k in range(1,self.n+1):
                left_end_point = self.a + (k - 1)* self.delta_X
                left_list.append(left_end_point)
            return left_list
        
        #Raise TypeError if input is not numerical
        except TypeError:
            print "\n<The entered value is not a number"

        Compute the value of Xk of each point using the
        left endpoint of each subinterval
        
recipes/Python/576897_RectangleMethod/recipe-576897.py