code: def get_signature_names(self):
          
          signature_expr = re.compile(r"^(META-INF/)(.*)(\.RSA|\.EC|\.DSA)$")
          signatures = []
  
          for i in self.get_files():
              if signature_expr.search(i):
                  if "{}.SF".format(i.rsplit(".", 1)[0]) in self.get_files():
                      signatures.append(i)
                  else:
                      log.warning("v1 signature file {} missing .SF file - Partial signature!".format(i))
  
          return signatures
docs: Return a list of the signature file names (v1 Signature / JAR
          Signature)
  
          :rtype: List of filenames matching a Signature