base.py 文件源码

def strip_future_imports(self, code):
        """
        Strips any of these import lines:

            from __future__ import <anything>
            from future <anything>
            from future.<anything>
            from builtins <anything>

        or any line containing:
            install_hooks()
        or:
            install_aliases()

        Limitation: doesn't handle imports split across multiple lines like
        this:

            from __future__ import (absolute_import, division, print_function,
                                    unicode_literals)
        """
        output = []
        # We need .splitlines(keepends=True), which doesn't exist on Py2,
        # so we use this instead:
        for line in code.split('\n'):
            if not (line.startswith('from __future__ import ')
                    or line.startswith('from future ')
                    or line.startswith('from builtins ')
                    or 'install_hooks()' in line
                    or 'install_aliases()' in line
                    # but don't match "from future_builtins" :)
                    or line.startswith('from future.')):
                output.append(line)
        return '\n'.join(output)