def list_(env=None, user=None):
cmd = _create_conda_cmd('<STR_LIT:list>', args=['<STR_LIT>'], env=env, user=user)<EOL>ret = _execcmd(cmd, user=user)<EOL>if ret['<STR_LIT>'] == <NUM_LIT:0>:<EOL><INDENT>pkg_list = json.loads(ret['<STR_LIT>'])<EOL>packages = {}<EOL>for pkg in pkg_list:<EOL><INDENT>pkg_info = pkg.split('<STR_LIT:->')<EOL>name, version, build = '<STR_LIT:->'.join(pkg_info[:-<NUM_LIT:2>]), pkg_info[-<NUM_LIT:2>], pkg_info[-<NUM_LIT:1>]<EOL>packages[name] = {'<STR_LIT:version>': version, '<STR_LIT>': build}<EOL><DEDENT>return packages<EOL><DEDENT>else:<EOL><INDENT>return ret<EOL><DEDENT>
List the installed packages on an environment

Returns
-------
    Dictionary: {package: {version: 1.0.0, build: 1 } ... }