python - how to solve AttributeError: '_Environ' object has no attribute 'has_key'

Question

def _is_dev_mode():
    # quick hack to check if the program is running in dev mode.
    # if 'has_key' in os.environ  
    if os.environ.has_key('SERVER_SOFTWARE') 
        or os.environ.has_key('PHP_FCGI_CHILDREN') 
        or 'fcgi' in sys.argv or 'fastcgi' in sys.argv 
        or 'mod_wsgi' in sys.argv:
           return False
    return True

---

in above code following error is shown

if os.environ.has_key('SERVER_SOFTWARE') 
AttributeError: '_Environ' object has no attribute 'has_key'

Answer 1

I supose you are working on python 3. In Python 2, dictionaries had a has_key() method. In Python 3, as the exception says, it no longer exists. You need to use the in operator:

if 'SERVER_SOFTWARE' in os.environ

here you have an example (py3k):

>>> import os
>>> if 'PROCESSOR_LEVEL' in os.environ: print(os.environ['PROCESSOR_LEVEL'])

6
>>> if os.environ.has_key('PROCESSOR_LEVEL'): print("fail")

Traceback (most recent call last):
  File "<pyshell#18>", line 1, in <module>
    if os.environ.has_key('PROCESSOR_LEVEL'): print("fail")
AttributeError: '_Environ' object has no attribute 'has_key'
>>>