Concerning Ruby coding style...

When one is writing a module for Ruby, is there a "preferred" style
for methods names?  The built-in ones seem to use all-lowercase
separated by underscores (i.e method_name), while contributed modules
seem to tend to use the Java-style (i.e. methodName).  I've wondered
if this is intentional, to help show the difference between built-in
and external classes.

Anyway... I'm getting to the point in Ruby where I'm starting to think
about contributing modules, and so I would like my code to be
consistent with whatever prevailing convention exists, if any.

thanks,
--Mirian