code: function checkMixin2(i) {
    const start = i;
    let l;
  
    if (i >= tokensLength) return 0;
  
    if (tokens[i].type === TokenType.EqualsSign) i++;
    else return 0;
  
    if (l = checkSC(i)) i += l;
  
    if (l = checkIdentOrInterpolation(i)) i += l;
    else return 0;
  
    if (l = checkSC(i)) i += l;
  
    if (l = checkBlock(i)) i += l;
    else {
      if (l = checkArguments(i)) i += l;
  
      if (l = checkSC(i)) i += l;
  
      if (l = checkBlock(i)) i += l;
      else return 0;
    }
  
    return i - start;
  }
docs: Check if token is part of a mixin
  @param {number} i Token's index number
  @return {number} Length of the mixin