'Constructor.
:param column_name:
Model field name
:param datamodel:
The datamodel access class
:param is_related_view:
Optional internal parameter to filter related views'

def __init__(self, column_name, datamodel, is_related_view=False):

    self.column_name = column_name
    self.datamodel = datamodel
    self.model = datamodel.obj
    self.is_related_view = is_related_view
