Checks if given attribute exists.

        Usage::

            >>> content = ["[Section A]\\n", "; Comment.\\n", "Attribute 1 = \\"Value A\\"\\n", "\\n", \
"[Section B]\\n", "Attribute 2 = \\"Value B\\"\\n"]
            >>> sections_file_parser = SectionsFileParser()
            >>> sections_file_parser.content = content
            >>> sections_file_parser.parse()
            <foundations.parsers.SectionsFileParser object at 0x234564563>
            >>> sections_file_parser.attribute_exists("Attribute 1", "Section A")
            True
            >>> sections_file_parser.attribute_exists("Attribute 2", "Section A")
            False

        :param attribute: Attribute to check existence.
        :type attribute: unicode
        :param section: Section to search attribute into.
        :type section: unicode
        :return: Attribute existence.
        :rtype: bool

def attribute_exists(self, attribute, section):
        """
        Checks if given attribute exists.

        Usage::

            >>> content = ["[Section A]\\n", "; Comment.\\n", "Attribute 1 = \\"Value A\\"\\n", "\\n", \
"[Section B]\\n", "Attribute 2 = \\"Value B\\"\\n"]
            >>> sections_file_parser = SectionsFileParser()
            >>> sections_file_parser.content = content
            >>> sections_file_parser.parse()
            <foundations.parsers.SectionsFileParser object at 0x234564563>
            >>> sections_file_parser.attribute_exists("Attribute 1", "Section A")
            True
            >>> sections_file_parser.attribute_exists("Attribute 2", "Section A")
            False

        :param attribute: Attribute to check existence.
        :type attribute: unicode
        :param section: Section to search attribute into.
        :type section: unicode
        :return: Attribute existence.
        :rtype: bool
        """

        if foundations.namespace.remove_namespace(attribute, root_only=True) in self.get_attributes(section,
                                                                                                    strip_namespaces=True):
            LOGGER.debug("> '{0}' attribute exists in '{1}' section.".format(attribute, section))
            return True
        else:
            LOGGER.debug("> '{0}' attribute doesn't exists in '{1}' section.".format(attribute, section))
            return False