Cfgrib fails to write endStep and stepUnits with error failed to set key "'endStep:int' to 0" and "failed to set key 'stepUnits:int' to 1"

[jsSvensson]

What happened?

I tried to write a cononical datasset and got the errors error failed to set key "'endStep:int' to 0" and "failed to set key 'stepUnits:int' to 1". The error seems to that eccodes does not recognize the keywords "endStep:int" and "stepUnits:int". The problem was solved when adding a line that removed ":int" from the message item this in message.py definition message_set:

def message_set(self, item: str, value: T.Any) -> None:
    arr = isinstance(value, (np.ndarray, T.Sequence)) and not isinstance(value, str)
    if arr:
        eccodes.codes_set_array(self.codes_id, item, value)
    else:
        if ":int" in item:
            newItem = item.split(":")[0]
        else: 
             newItem=item
        eccodes.codes_set(self.codes_id, newItem, value)

My suggestion is to add a similar piece of code to the next update of cfgrib.

What are the steps to reproduce the bug?

Read a canonical grib message and try to print write it out again with:

from cfgrib.xarray_to_grib import to_grib
to_grib(ds, 'test.grib') 

I used hybrid level data on regular lat-lon from ECMWF web API. To write model level data one needs to make a template for that grid in eccodes/samples-library, e.g. by change the template for regular_ll_sfc_grib2.tmpl with e.g.
grib_set -s typeOfLevel=hybrid,level=137 regular_ll_sfc_grib2.tmpl regular_ll_ml_grib2.tmpl.

Version

cfgrib v0.9.14.1. eccodes 2.38.3

Platform (OS and architecture)

Ubuntu 20.04.6 LTS

Relevant log output

Accompanying data

No response

Organisation

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