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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def get_default_compartment(model):
 """Return what the default compartment should be set to. If some compounds have no compartment, unique compartment name is returned to avoid collisions. """

    default_compartment = 'c'
    default_key = set()
    for reaction in model.reactions:
        equation = reaction.equation
        if equation is None:
            continue

        for compound, _ in equation.compounds:
            default_key.add(compound.compartment)

    if None in default_key and default_compartment in default_key:
        suffix = 1
        while True:
            new_key = '{}_{}'.format(default_compartment, suffix)
            if new_key not in default_key:
                default_compartment = new_key
                break
            suffix += 1

    if None in default_key:
        logger.warning(
            'Compound(s) found without compartment, default'
            ' compartment is set to {}.'.format(default_compartment))
    return default_compartment