Field 'id' expected a number but got ''.

pd=User.objects.get(id=user_id)

def editConsultant(request): 
    if request.method=='POST':
        name=request.POST.get('name')
        phone=request.POST.get('phone')
        email=request.POST.get('email')
        user_id=request.POST.get('user_id')
        status=request.POST.get('status')
        role=request.POST.get('role')
        engagements=request.POST.getlist('engagement')
        if engagements!=[]:
            
 
engagements=Engagement.objects.filter(engagementName__in=engagements).values_list('id',flat=True)
            pd=User.objects.get(id=user_id)
            k=pd.engagement.all().values_list('id',flat=True)
            if k:
                pd.engagement.remove(*k)
            pd.engagement.set(engagements)
            pd.save()
         j=User.objects.filter(id=user_id)
         j.update(status=status,role=role,first_name=name,phone=phone,email=email)
         return redirect('listconsultant')

<label>Account</label>
<span style="color:#ff0000">*</span>
<select  placeholder="Engagement" name="engagement" {% if userdetails %} value={{userdetails.Engagement}} {% endif %} class="dropdown-item">
    <option value="None">---Select Account------</option>
    {% for i in engagement %}
        <option id="parentclientId" value="{{i.engagementName}}">{{i.engagementName}}</option>
    {% endfor %}
    </select>
</div>

<div class="form-group">
                                <label>Account</label>
                                <select  placeholder="Engagement"class="dropdown-item" name="engagement" id="parentclientId"  >
                                    <option disabled="true">New Acc</option>
                                    {% for i in engagement %}
                                        <option value="{{i.id}}">{{i.engagementName}}</option>
                                    {% endfor %}    
                                </select>                                  
                                </div>