class Catalogue:
    def __init__(self, name):
        self.name = name
        self.products = []

    def add_product(self, product_name):
        self.products.append(product_name)

    def get_by_letter(self, first_letter):
        result = [element for element in self.products if element.startswith(first_letter)]
        return result

    def __repr__(self):
        self.products.sort()
        result = "Items in the {0} catalogue:\n" \
                 "{1}".format(self.name, '\n'.join(self.products))
        return result