'Returns True if coordinates is valid and can be walked to.
Args:
wilderness: the wilderness script
coordinates (tuple): the coordinates to check as (x, y) tuple.
Returns:
bool: True if the coordinates are valid'

def is_valid_coordinates(self, wilderness, coordinates):

    (x, y) = coordinates
    if (x < 0):
        return False
    if (y < 0):
        return False
    return True
