VCS_get_parent

	Name		: VCS_get_parent

	Synopsis	: dt_Handle VCS_get_parent ( can_seq )
                          dt_Handle can_seq

	Arguments	: can_seq	Sequence of canonical SMILES string
                                        objects.

	Description	: Returns a sequence of canonical SMILES string
			  objects ( usually only one ) which results from 
			  applying the function VCS_is_salt() to each 
			  unique string, in the input sequence, in turn.
			  If VCS_is_salt returns TRUE i.e. it is a salt or
			  solvate, the object is deleted from the sequence.
                          If there is only one object in the input
			  sequence it is returned without checking. If all
			  components appear to be salts i.e. the number of
			  objects becomes zero, the original sequence, with
			  duplicates removed is returned.

	Restriction	:

	Error		:

	Related
	Modules		: VCS_is_salt