It is vital that it is done at the beginning of each ballet session, including before a performance.
1	It	it	PRON	PRP	Case=Nom|Gender=Neut|Number=Sing|Person=3|PronType=Prs	3	expl	3:expl	Discourse=elaboration-additional:23->18:1|Entity=(29-abstract-new-cf3-1-cata)
2	is	be	AUX	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	3	cop	3:cop	_
3	vital	vital	ADJ	JJ	Degree=Pos	0	root	0:root	_
4	that	that	SCONJ	IN	_	7	mark	7:mark	_
5	it	it	PRON	PRP	Case=Nom|Gender=Neut|Number=Sing|Person=3|PronType=Prs	7	nsubj:pass	7:nsubj:pass	Entity=(29-abstract-acc:com-cf3-3-coref(26-event-giv:act-cf1*-1-coref)
6	is	be	AUX	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	7	aux:pass	7:aux:pass	_
7	done	do	VERB	VBN	Tense=Past|VerbForm=Part|Voice=Pass	3	csubj	3:csubj	_
8	at	at	ADP	IN	_	10	case	10:case	_
9	the	the	DET	DT	Definite=Def|PronType=Art	10	det	10:det	Entity=(30-time-new-cf4-2-sgl
10	beginning	beginning	NOUN	NN	Number=Sing	7	obl	7:obl:at	_
11	of	of	ADP	IN	_	14	case	14:case	_
12	each	each	DET	DT	PronType=Tot	14	det	14:det	Entity=(31-event-new-cf5-3-sgl
13	ballet	ballet	NOUN	NN	Number=Sing	14	compound	14:compound	Entity=(1-abstract-giv:inact-cf2-1-coref)
14	session	session	NOUN	NN	Number=Sing	10	nmod	10:nmod:of	Entity=31)30)29)|SpaceAfter=No
15	,	,	PUNCT	,	_	19	punct	19:punct	_
16	including	include	VERB	VBG	VerbForm=Ger	19	case	19:case	_
17	before	before	ADP	IN	_	19	case	19:case	_
18	a	a	DET	DT	Definite=Ind|PronType=Art	19	det	19:det	Entity=(32-event-new-cf6-2-sgl
19	performance	performance	NOUN	NN	Number=Sing	7	obl	7:obl:including_before	Entity=32)|SpaceAfter=No
20	.	.	PUNCT	.	_	3	punct	3:punct	_
