Get pip location based on environment `name` or `prefix`.

def _pip_cmd(self, name=None, prefix=None):
        """Get pip location based on environment `name` or `prefix`."""
        if (name and prefix) or not (name or prefix):
            raise TypeError("conda pip: exactly one of 'name' ""or 'prefix' "
                            "required.")

        if name and self.environment_exists(name=name):
            prefix = self.get_prefix_envname(name)

        if sys.platform == 'win32':
            python = join(prefix, 'python.exe')  # FIXME:
            pip = join(prefix, 'pip.exe')        # FIXME:
        else:
            python = join(prefix, 'bin/python')
            pip = join(prefix, 'bin/pip')

        cmd_list = [python, pip]

        return cmd_list