<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def id_to_name(id):
 """ Convert a PDG ID to a printable string. """

    name = pdgid_names.get(id)
    if not name:
        name = repr(id)
    return name