ifier rubyid_model_field_namespace'>model_field_namespace</span><span class='period'>.</span><span class='id identifier rubyid_const_defined?'>const_defined?</span><span class='lparen'>(</span><span class='id identifier rubyid_constant'>constant</span><span class='comma'>,</span> <span class='kw'>false</span><span class='rparen'>)</span>
      <span class='kw'>return</span> <span class='id identifier rubyid_model_field_namespace'>model_field_namespace</span><span class='period'>.</span><span class='id ident