check if segment selection is a valid option
     
    
    Usage
    check_segment_trial(vesalius_assay, trial = "last")
 
    
    Arguments
- vesalius_assay
- a vesalius_assay object 
- trial
- string - trial selection parse by user 
 
    
    Value
    data frame contain selected trial
     
    
    Details
    check if the trial selection exists in territory slot
Default is last that will take the last entry. This function
will also reformat to only include the necessay information.