Itches with subfields

[renaud....@gmail.com]

Hi, 

I'm new with Python but I work with MARC since some years.

I'm working about a institutional repository where metadata of all publications stored in MARCXML (repository based on Fedora Commons)

So I try to use "pymarc" to easily manage metadata. 

At this time, I need to delete some subfields. No problem method exists in pymarc.files ...

But my fields can contains multiple same code subfields. By example : 

<marc:field tag="955" ind1=" " ind2=" "> <!-- used to store document type and subtypes -->

  <marc:subfield code="a">Periodical article</marc:subfield> <!-- document type -->

  <marc:subfield code="b">Published</marc:subfield>  <!-- document subtype -->

  <marc:subfield code="b">Clinical trial</marc:subfield> <!-- document subtype -->

</marc:field>

In my case, I need to delete "Clinical trial". If I use "delete_subfield" method, I can't be sure that the I will delete the correct subfield.

So I wrote a little method to delete subfield depending of the value : 

def delete_sepcific_subfields(field, code, value):
    all_idx = [i for i in range(len(field.subfields)) if (i % 2 == 0 and field.subfields[i] == code and field.subfields[i+1] == value)]
    for idx in all_idx:
        field.subfields.pop(idx+1) #pop value
        field.subfields.pop(idx)   #pop code
    return field

This method is working fine, but I would know if it's a best way to do that using basic "pymarc" package ?
As I'm very lazy :-) I would like to know if is it a chance to include a such method into "pymarc" rather than copy-paste this code on all my project.

Thanks (and sorry for my english ^^)
Regards

Renaud