def get_cfcompliant_units(units, prefix='<STR_LIT>', suffix='<STR_LIT>'):
compliant_units = units<EOL>for gcunits, udunits in UNITS_MAP_CTM2CF:<EOL><INDENT>compliant_units = str.replace(compliant_units, gcunits, udunits)<EOL><DEDENT>return prefix + compliant_units + suffix<EOL>
Get equivalent units that are compatible with the udunits2 library
(thus CF-compliant).

Parameters
----------
units : string
    A string representation of the units.
prefix : string
    Will be added at the beginning of the returned string
    (must be a valid udunits2 expression).
suffix : string
    Will be added at the end of the returned string
    (must be a valid udunits2 expression).

Returns
-------
A string representation of the conforming units.

References
----------
The udunits2 package : http://www.unidata.ucar.edu/software/udunits/

Notes
-----
This function only relies on the table stored in :attr:`UNITS_MAP_CTM2CF`.
Therefore, the units string returned by this function is not certified to
be compatible with udunits2.

Examples
--------
>>> get_cfcompliant_units('molec/cm2')
'count/cm2'
>>> get_cfcompliant_units('v/v')
'1'
>>> get_cfcompliant_units('ppbC', prefix='3')
'3ppb