How to use the gpaw.PW function in gpaw

def run_if_interactive(self):
        if self.structure.calc is None:
            kpoints = self.input["kpoints"]
            if isinstance(kpoints, str):
                kpoints = (
                    self.input["kpoints"].replace("[", "").replace("]", "").split()
                )
            self._create_working_directory()
            calc = GPAW(
                mode=PW(float(self.input["encut"])),
                xc=self.input["potential"],
                occupations=MethfesselPaxton(width=float(self.input["sigma"])),
                kpts=kpoints,
                txt=self.working_directory + "/" + self.job_name + ".txt",
            )
            self.structure.set_calculator(calc)
        self.status.running = True
        self.structure.calc.calculate(self.structure)
        self.interactive_collect()

from ase.dft.bandgap import bandgap
from gpaw import GPAW, PW


if Path('database.db').is_file():
    Path('database.db').unlink()

structures = ['Si', 'Ge', 'C']
db = connect('database.db')

for f in structures:
    db.write(bulk(f))

for row in db.select():
    atoms = row.toatoms()
    calc = GPAW(mode=PW(400),
                kpts=(4, 4, 4),
                txt=f'{row.formula}-gpaw.txt', xc='LDA')
    atoms.calc = calc
    atoms.get_stress()
    filter = ExpCellFilter(atoms)
    opt = BFGS(filter)
    opt.run(fmax=0.05)
    db.write(atoms=atoms, relaxed=True)


for row in db.select(relaxed=True):
    atoms = row.toatoms()
    calc = GPAW(mode=PW(400),
                kpts=(4, 4, 4),
                txt=f'{row.formula}-gpaw.txt', xc='LDA')
    atoms.calc = calc

from ase.build import bulk
from gpaw import GPAW, PW

atoms = bulk('Ag')
calc = GPAW(mode=PW(350), kpts=[8, 8, 8], txt='gpaw.bulk.Ag.txt',
            setups={'Ag': '11'})
atoms.calc = calc
atoms.get_potential_energy()
calc.write('bulk.Ag.gpw')

from ase.constraints import ExpCellFilter
from ase.io import write
from ase.optimize import BFGS
from ase.spacegroup import crystal
from gpaw import GPAW, PW

a = 4.6
c = 2.95

# Rutile TiO2:
atoms = crystal(['Ti', 'O'], basis=[(0, 0, 0), (0.3, 0.3, 0.0)],
                spacegroup=136, cellpar=[a, a, c, 90, 90, 90])
write('rutile.traj', atoms)

calc = GPAW(mode=PW(800), kpts=[2, 2, 3],
            txt='gpaw.rutile.txt')
atoms.calc = calc

opt = BFGS(ExpCellFilter(atoms), trajectory='opt.rutile.traj')
opt.run(fmax=0.05)

calc.write('groundstate.rutile.gpw')

print('Final lattice:')
print(atoms.cell.get_bravais_lattice())

import numpy as np
from gpaw import GPAW, PW

from ase.calculators.dftd3 import DFTD3
from ase.build import bulk
from ase.constraints import UnitCellFilter

from ase.optimize import LBFGS

np.random.seed(0)

diamond = bulk('C')
diamond.rattle(stdev=0.1, seed=0)
diamond.cell += np.random.normal(scale=0.1, size=(3,3))
dft = GPAW(xc='PBE', kpts=(8,8,8), mode=PW(400))
d3 = DFTD3(dft=dft)
diamond.calc = d3

ucf = UnitCellFilter(diamond)

opt = LBFGS(ucf, logfile='diamond_opt.log', trajectory='diamond_opt.traj')
opt.run(fmax=0.05)