code: def merge_flags(cfg1, cfg2):
      """Merge values from cffi config flags cfg2 to cf1
  
      Example:
          merge_flags({"libraries": ["one"]}, {"libraries": ["two"]})
          {"libraries": ["one", "two"]}
      """
      for key, value in cfg2.items():
          if key not in cfg1:
              cfg1[key] = value
          else:
              if not isinstance(cfg1[key], list):
                  raise TypeError(
                      "cfg1[%r] should be a list of strings" % (key,)
                  )
              if not isinstance(value, list):
                  raise TypeError(
                      "cfg2[%r] should be a list of strings" % (key,)
                  )
              cfg1[key].extend(value)
      return cfg1
  
imports: import sys, os, subprocess
  from .error import PkgConfigError
label_desc: Use image node_id 1 for calling a global function with example usage: merge_flags(cfg1, cfg2) and returns: cfg1