Define a class that meets the following specifications. Class name: WaterBody Class constructor parameter: 1. int/float Assign this number to the instance attribute volume The class has class attributes RHO = 997 and G = 9.81. Define a class method for the WaterBody class that meets the following specifications. Method name : get_hydrostatic_pressure Method parameter: 1. float Method type: Class method Return value: 1. float Using the input float, the depth. calculate and return the hydrostatic pressure. Hydrostatic pressure a given depth = RHO*G*depth If the depth is less than 0, the static method should raise an InvalidDepthError. Define a instance method for the WaterBody class that meets the following specifications. Method name: get_water_mass Method type: Instance method Return value: 1. Float This method should return the mass of the waterbody given that mass = RHO* volume

Here's a possible implementation of the WaterBody class that meets the given specifications:

class WaterBody:
    RHO = 997
    G = 9.81
    
    def __init__(self, volume):
        self.volume = volume
        
    @classmethod
    def get_hydrostatic_pressure(cls, depth):
        if depth < 0:
            raise InvalidDepthError("Depth can't be negative")
        return cls.RHO * cls.G * depth
    
    def get_water_mass(self):
        return self.RHO * self.volume

In this implementation, the class has a constructor that takes an int or float argument and assigns it to the instance attribute `volume`. The class also has two class attributes `RHO` and `G`, which are used in the methods to calculate the hydrostatic pressure and the water mass.

The `get_hydrostatic_pressure` method is a class method that takes a float argument `depth`, and calculates the hydrostatic pressure at that depth using the formula `RHO*G*depth`. If the depth is less than 0, it raises an `InvalidDepthError`. This method is decorated with `@classmethod` to indicate that it operates on the class, not on an instance of the class.

The `get_water_mass` method is an instance method that returns the mass of the waterbody using the formula `RHO*volume`. This method doesn't take any arguments, but operates on the instance attributes.