<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def get_null_snr(self):
 		""" 		Get the coherent Null SNR for this row. 		"""

		null_snr_sq = (numpy.asarray(self.get_sngl_snrs().values())**2)\
                             .sum() - self.snr**2
		if null_snr_sq < 0:
			return 0
		else:
			return null_snr_sq**(1./2.)