optimizer.py 文件源码

def add_import(tree, name, asname):
    # import fat as __fat__
    import_node = ast.Import(names=[ast.alias(name=name, asname=asname)],
                      lineno=1, col_offset=1)
    for index, node in enumerate(tree.body):
        if (index == 0 and isinstance(node, ast.Expr)
           and isinstance(node.value, ast.Constant)
           and isinstance(node.value.value, str)):
            # docstring
            continue
        if (isinstance(node, ast.ImportFrom) and node.module == '__future__'):
            # from __future__ import ...
            continue
        tree.body.insert(index, import_node)
        break
    else:
        # body is empty or only contains __future__ imports
        tree.body.append(import_node)