Python connection

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Consider the following snippet from a Python module:
from pyPGSQL import libpq
cn = libpq.PQconnectdb("dbname='db', host='xxx'")

At this point, I get the error:
invalid connection option ", host

If I'm reading the documentation for libpq correctly (it's safe to assume I'm
not), host appears to be the correct parameter for specifying the server
running PostgreSQL. What am I doing wrong
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