def add(self, elem, replace=False):
        """Add a requirement.

        :param elem: a string or :class:`Requirement` instance.
        :param replace: if `True`, packages in the set with the same name will
            be removed first.
        """
        if isinstance(elem, text_type):
            elem = Requirement.coerce(elem)
        if replace and elem in self:
            self.remove(elem)
        super(Requirements, self).add(elem)
def get_remote_url(cls, location):
        """
        Return URL of the first remote encountered.

        Raises RemoteNotFoundError if the repository does not have a remote
        url configured.
        """
        # We need to pass 1 for extra_ok_returncodes since the command
        # exits with return code 1 if there are no matching lines.
        stdout = cls.run_command(
            ['config', '--get-regexp', r'remote\..*\.url'],
            extra_ok_returncodes=(1, ),
            show_stdout=False,
            stdout_only=True,
            cwd=location,
        )
        remotes = stdout.splitlines()
        try:
            found_remote = remotes[0]
        except IndexError:
            raise RemoteNotFoundError

        for remote in remotes:
            if remote.startswith('remote.origin.url '):
                found_remote = remote
                break
        url = found_remote.split(' ')[1]
        return url.strip()