Estoy tratando de instalar una biblioteca de Python usandopip, obteniendo un error SSL:

~/projects/base  pre-master±  pip install xdict

Collecting xdict
  Could not fetch URL https://pypi.python.org/simple/xdict/: There was a problem confirming the ssl certificate: [SSL: TLSV1_ALERT_PROTOCOL_VERSION] tlsv1 alert protocol version (_ssl.c:590) - skipping
  Could not find a version that satisfies the requirement xdict (from versions: )
No matching distribution found for xdict

versión de pip: pip 9.0.1

¿Cómo soluciono este error?