<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def get_resolution(pdb_id):
 """Quick way to get the resolution of a PDB ID using the table of results from the REST service Returns infinity if the resolution is not available. Returns: float: resolution of a PDB ID in Angstroms TODO: - Unit test """


    pdb_id = pdb_id.upper()
    if pdb_id not in _property_table().index:
        raise ValueError('PDB ID not in property table')
    else:
        resolution = _property_table().ix[pdb_id, 'resolution']
        if pd.isnull(resolution):
            log.debug('{}: no resolution available, probably not an X-ray crystal structure')
            resolution = float('inf')

    return resolution