code: def _filter_netcdf4_metadata(self, mdata_dict, coltype, remove=False):
          
          # Coerce boolean types to integers
          for key in mdata_dict:
              if type(mdata_dict[key]) == bool:
                  mdata_dict[key] = int(mdata_dict[key])
          if (coltype == type(' ')) or (coltype == type(u' ')):
              remove = True
          # print ('coltype', coltype, remove, type(coltype), )
          if u'_FillValue' in mdata_dict.keys():
              # make sure _FillValue is the same type as the data
              if remove:
                  mdata_dict.pop('_FillValue')
              else:
                  mdata_dict['_FillValue'] = np.array(mdata_dict['_FillValue']).astype(coltype)
          if u'FillVal' in mdata_dict.keys():
              # make sure _FillValue is the same type as the data
              if remove:
                  mdata_dict.pop('FillVal')
              else:
                  mdata_dict['FillVal'] = np.array(mdata_dict['FillVal']).astype(coltype)
          return mdata_dict
docs: Filter metadata properties to be consistent with netCDF4.
          
          Notes
          -----
          removed forced to True if coltype consistent with a string type
          
          Parameters
          ----------
          mdata_dict : dict
              Dictionary equivalent to Meta object info
          coltype : type
              Type provided by _get_data_info
          remove : boolean (False)
              Removes FillValue and associated parameters disallowed for strings
              
          Returns
          -------
          dict
              Modified as needed for netCDf4