'Returns HMAC-SHA1 signature as specified at:
http://oauth.net/core/1.0a/#rfc.section.9.2.
:param str method:
HTTP method of the request to be signed.
:param str base:
Base URL of the request without query string an fragment.
:param dict params:
Dictionary or list of tuples of the request parameters.
:param str consumer_secret:
:attr:`.core.Consumer.secret`
:param str token_secret:
Access token secret as specified in
http://oauth.net/core/1.0a/#anchor3.
:returns:
The signature string.'

@classmethod
def create_signature(cls, method, base, params, consumer_secret, token_secret=''):

    base_string = _create_base_string(method, base, params)
    key = cls._create_key(consumer_secret, token_secret)
    hashed = hmac.new(six.b(key), base_string.encode('utf-8'), hashlib.sha1)
    base64_encoded = binascii.b2a_base64(hashed.digest())[:(-1)]
    return base64_encoded
