def subs(self, path):
<EOL>if type(path) == int or type(path) == float:<EOL><INDENT>return path<EOL><DEDENT>for s in self.init_substitutes:<EOL><INDENT>if path.startswith(s):<EOL><INDENT>path = path.replace(s,self.init_substitutes[s], <NUM_LIT:1>)<EOL><DEDENT><DEDENT>for s in self.substitutes:<EOL><INDENT>if s in path:<EOL><INDENT>path = path.replace(s,self.substitutes[s])<EOL><DEDENT><DEDENT>return path<EOL>
Search the strings in a config file for a substitutable value, e.g. 
"morphologies_dir": "$COMPONENT_DIR/morphologies",