class_docstr: The joiner setting defines a joining condition between conceptual tables
  
  You might want to join several tables by specifying the columns that match
  each other or might want to join images in an image set by matching
  their metadata. The joiner takes a dictionary of lists of column names
  or metadata keys where the dictionary key holds the table or image name
  and the list of values holds the names of table columns or metadata keys.
  
  The joiner's value is, conceptually, a list of dictionaries where each
  dictionary in the list documents how to join one column or metadata key
  in one of the tables or images to the others.
  
  The conceptual value is a list of dictionaries of unicode string keys
  and values (or value = None). This can be encoded using str() and
  can be decoded using eval.
code: def build_string(cls, dictionary_list):
      return str(dictionary_list)
  
file_path: CellProfiler/src/subpackages/core/cellprofiler_core/setting/_joiner.py
imports: from ._setting import Setting
  from ._validation_error import ValidationError
label_desc: Use image node_id 5 for calling the Joiner obj's underlying member method code with example usage: obj.build_string(cls, dictionary_list) and returns: str