isError Error wrapper for VNAKit.VNAKit static methods which return
a VNAKIT_RESULT which will either be VNAKIT_SUCCESS or an
error code. Wrapper detects and prints the error code
[] = isError(ctxt, errcode)
Inputs:
ctxt: [string] Context for the error message. Usually the
name of the function
errcode: [VNAKit.VNAKIT_RESULT] error code of VNAKit method
Output:
None