docs: def reset_less_significant(self, significant_version):
  		"""
  		Reset to zero all version info less significant than the
  		indicated version.
  
  		>>> ver = SummableVersion('3.1.2')
  		>>> ver.reset_less_significant(SummableVersion('0.1'))
  		>>> str(ver)
  		'3.1'
  		"""
  		def nonzero(x):
  			return x != 0
  		version_len = 3  # strict versions are always a tuple of 3
  		significant_pos = rfind(nonzero, significant_version.version)
  		significant_pos = version_len + significant_pos + 1
  		self.version = (
  			self.version[:significant_pos]
  			+ (0,) * (version_len - significant_pos))