title: convert kotlin data class into json string
body: <p>I have a data class with this class definition</p>
  
  <pre><code>data class AccountInfoResponse(
      @SerializedName("userprofile") val userprofiles: ArrayList&lt;UserProfile&gt;,
      @SerializedName("userpatients") val userpatients: ArrayList&lt;UserPatient&gt;
  )
  
  class UserPatient (
      @SerializedName("sex") val sex: String,
      @SerializedName("date of birth") val date_of_birth: String,
      @SerializedName("address") val address: String,
      @SerializedName("patientID") val patientId: Int,
      @SerializedName("first name") val first_name: String,
      @SerializedName("clinicName") val clinic_name: String,
      @SerializedName("clinicID") val clinicId: Int,
      @SerializedName("mobile") val mobile: String,
      @SerializedName("last name") val last_name: String
  )
  </code></pre>
  
  <p>I need to convert this class to be json string like this</p>
  
  <pre><code>{"userpatients":[{"sex":"male","date of birth":"2010-01-03","image":"","clinics":[1],"primary_provider":[{"clinic":1,"patient":1,"providers":1}],"role":"patient","last name":"John","address":"300 east main st.  San Jose, Ca 95014","first name":"John","username":"John","email":"sameh88@ensofia.com","mobile":"+88083918427"}],"userpatients":[{"sex":"female","date of birth":"2000-01-01","address":"fawal st1","patientID":1,"first name":"john","clinicName":"light house peds","clinicID":1,"mobile":"8056688042","last name":"john"}]}
  </code></pre>