Add meta data to MD block

[gual11]

In mdf4 format there ist also the possibility to store meta data in e tags.
Is it possible to write new e Tags with this asammdf library?

this is an example structure:
mdf_example.txt

I want to add more e tags to this, to store more metadata

[danielhrisca]

Just assign that xml string to the channel comment

ch.comment = "<CNComment>..."

[gual11]

and I don't want to add a comment to the channel, but to the header in the meta data block

[danielhrisca]

mdf = MDF('my_file.mf4')

first_group = mdf.groups[0]
first_channel = first_group.channels[0]

first_channel.comment = """<CNcomment>
<!-- required substitute for TXBLOCK -->
<TX>Channel of great importance.</TX>
<!-- channel comment specific tags -->
<names>
<display>RPM</display>
</names>
<raster min="1" max="2">1.5</raster>
<!-- optional general tags -->
<common_properties>
<e name="blub" ci="1" desc="Blubber factor">17</e>
<tree name="user" desc="user doing the recording">
<e name="first name">John</e>
<e name="last name">Smith</e>
</tree>
</common_properties>
<extensions>
<extension ci="2">
<vendor_tag xmlns="http://vendor2/my-namespace">
<something/>
</vendor_tag>
</extension>
</extensions>
</CNcomment>"""

header = mdf.header
header.comment = """<HDcomment><TX>new header comment</TX></HDcomment>"""

mdf.save('new_comment.mf4')
mdf.close()

[gual11]

Thanks for the fast reply, I tested it, it goes in the right direction, but still not what I want.
Where the meta data is stored with this syntax is in the signal group, but I want to store it in the header group:

[gual11]

okay I found the .header parameter, I am going to try with that

[danielhrisca]

That is exactly what the example above shows