def METHOD_NAME(self,k):
    """
    REQUIRED INPUT:
        - net radiation
        - vapour pressure deficit
        - sgamma (slope of staturation vapour function)
        - aeroRes (aerodynamic resistance)
    PARAMETERS:
        - gamma (psychrometric constant)
        - Cp (specific heat of moist air, 1.01 MJkg-1K-1)
        - rhoA (density of air)
        - rhoW (density of water)
        - lamda (latent heat of vaporisation)
    """
    nom = self.sgamma * self.Rn + self.rhoA * self.Cp * self.vpd / self.aeroRes
    denom = self.rhoW * self.lamda * (self.sgamma + self.gamma)
    self.EpDay = (nom / denom) * 1000
    self.EpD_[k] = self.EpDay