code: def get_protein_targets_only(target_chembl_ids):
      
      protein_targets = {}
      for target_chembl_id in target_chembl_ids:
          target = query_target(target_chembl_id)
          if 'SINGLE PROTEIN' in target['target_type']:
              protein_targets[target_chembl_id] = target
      return protein_targets
docs: Given list of ChEMBL target ids, return dict of SINGLE PROTEIN targets
  
      Parameters
      ----------
      target_chembl_ids : list
          list of chembl_ids as strings
  
      Returns
      -------
      protein_targets : dict
          dictionary keyed to ChEMBL target ids with lists of activity ids