Only vowels beginning with ākāra are true svaras; ṣaḍja and the like exist for the pronunciation of these vowels.
Body (pseudocode)
def is_true_svara(sound):
return sound.type == 'vowel' and sound.starts_with == 'akara'
Inputs / output
sound
object
→ is_true_svara
Evidence (1)
p. vol_I_p024 · #2256« only (vowels) beginning with ākāra are svaras. şadja and the like are there for the pronunciation of (vowels) beginning with ākāra »