def __init__(self, constraints, symbols=None, *args, **kwargs):
super().__init__(*args, **kwargs)<EOL>assert isinstance(constraints, ConstraintSet)<EOL>self._constraints = constraints<EOL>if symbols is None:<EOL><INDENT>self._symbols = {}<EOL><DEDENT>else:<EOL><INDENT>self._symbols = dict(symbols)<EOL><DEDENT>
Builds a memory.

:param constraints:  a set of constraints
:param symbols: Symbolic chunks