code: public JBBPDslBuilder BitArray(final String bitLenExpression, final String sizeExpression) {
      return this.BitArray(null, bitLenExpression, assertExpressionChars(sizeExpression));
    }
docs: Add anonymous bit array with size calculated through expression.
  
  @param bitLenExpression expression to calculate length of the bit field, must not be null
  @param sizeExpression   expression to be used to calculate array size, must not be null
  @return the builder instance, must not be null