def gasfvf2(unit='unit1', z=0.8, temp=186, pressure=2000):
  """
  Gas FVF calculated in other units
  unit: choice of units (unit1: RB/scf, unit2: res m3/std m3)
  for unit1, inputs temp in Rankine (Fahrenheit + 460), pressure in psia or psig
  for unit2, inputs temp in Kelvin, pressure in psia or psig
  """
  if unit == 'unit1':
    return(0.00503676 * z * temp / pressure) 
  if unit == 'unit2':
    return(0.350958 * z * temp / pressure)