@staticmethod
def check_dim_sels(var_dims, dim_sels, num_dims):
    """
        Extract dimension selections and check they're valid.
        args...
            var_dims: variable dimensions
            dim_sels: dimension selections (see get_request_url)
            num_dims: number of dimensions
        """
    dims_ok = True
    for idim in range(num_dims):
        if dim_sels[idim, 0] < 0 or dim_sels[idim, 1] < 0 or dim_sels[idim, 2
            ] < 0:
            dims_ok = False
        if dim_sels[idim, 0] > var_dims[idim] - 1 or dim_sels[idim, 2
            ] > var_dims[idim] - 1:
            dims_ok = False
        if dim_sels[idim, 2] < dim_sels[idim, 0]:
            dims_ok = False
        if dim_sels[idim, 0] != dim_sels[idim, 2] and dim_sels[idim, 1
            ] > dim_sels[idim, 2]:
            dims_ok = False
    return dims_ok
