'Set the consumer_key and consumer_secret for this instance
Args:
consumer_key:
The consumer_key of the twitter account.
consumer_secret:
The consumer_secret for the twitter account.
access_token_key:
The oAuth access token key value you retrieved
from running get_access_token.py.
access_token_secret:
The oAuth access token\'s secret, also retrieved
from the get_access_token.py run.'

def SetCredentials(self, consumer_key, consumer_secret, access_token_key=None, access_token_secret=None):

    self._consumer_key = consumer_key
    self._consumer_secret = consumer_secret
    self._access_token_key = access_token_key
    self._access_token_secret = access_token_secret
    self._oauth_consumer = None
    if ((consumer_key is not None) and (consumer_secret is not None) and (access_token_key is not None) and (access_token_secret is not None)):
        self._signature_method_plaintext = oauth.SignatureMethod_PLAINTEXT()
        self._signature_method_hmac_sha1 = oauth.SignatureMethod_HMAC_SHA1()
        self._oauth_token = oauth.Token(key=access_token_key, secret=access_token_secret)
        self._oauth_consumer = oauth.Consumer(key=consumer_key, secret=consumer_secret)
