Field contains list and values of it are shown in one symbol I'm developing a drupal module and there's a problem. I need to make a content type with some fields and one of them should have list with string values. But when I try to create content and choose new content type I created, I see list and there are values contains first symbol of the string that I need. 

coursebook.info.yml

name: Course Book
description: Course book
type: module
core: 8.x
package: Course book module


field.storage.node.field_disciplines.yml

langcode: en
dependencies:
  enforced:
    module:
    - coursebook
  module:
  - node
id: node.field_disciplines
field_name: field_disciplines
entity_type: node
type: list_string
settings:
  allowed_values: { "1":'A', "2":'Bb', "3":'Cccc'}
  max_length: 1000
module: core
locked: false
cardinality: 100


field.field.node.coursebook.field_disciplines.yml

langcode: en
dependencies:
  config:
  - field.storage.node.field_disciplines
  - node.type.coursebook
id: node.coursebook.field_disciplines
field_name: field_disciplines
entity_type: node
bundle: coursebook
label: 'disciplines'
description: 'Type disciplines here'
required: false
default_value: 'example'
settings: { }
field_type: list_string


core.entity_view_display.node.coursebook.default.yml

langcode: en
status: true
dependencies:
  config:
  - field.field.node.coursebook.field_year
  - field.field.node.coursebook.field_semester
  - node.type.coursebook
id: node.coursebook.default
targetEntityType: node
bundle: coursebook
mode: default
content:
  field_year:
    label: hidden
    type: string
    weight: 0
    settings: {  }
    third_party_settings: {  }
  field_semester:
    label: hidden
    type: string
    weight: 1
    settings: {  }
    third_party_settings: {  }
  field_disciplines:
    label: hidden
    type: string
    weight: 2
    settings: {  }
    third_party_settings: {  }


core.entity_form_display.node.coursebook.default.yml

langcode: en
status: true
dependencies:
  config:
  - field.field.node.coursebook.field_year
  - field.field.node.coursebook.field_semester
  - node.type.coursebook
id: node.coursebook.default
targetEntityType: node
bundle: coursebook
mode: default
content:
  field_year:
    type: string_textfield
    weight: 0
    settings:
      size: 30
      placeholder: 'example'
    third_party_settings: {  }
  field_semester:
    type: string_textfield
    weight: 1
    settings:
      size: 30
      placeholder: 'example'
    third_party_settings: {  }
  field_disciplines:
    type: string_textfield
    weight: 2
    settings:
      size: 30
      placeholder: 'example'
    third_party_settings: {  }
hidden: { }


And what I see - 
But i shuold see this list:

allowed_values: { "1":'A', "2":'Bb', "3":'Cccc'}


There are only files that describe problem field. I hope you understand my problem. I develop my module using this manual: https://medium.com/touch4it/custom-content-type-with-custom-fields-for-your-drupal-8-module-9478fd018f76
You need to have the allowed values settings in the following format:

allowed_values:
  -
    value: '1'
    label: A
  -
    value: '2'
    label: 'Bb'
  -
    value: '3'
    label: Ccccc


The quotes don't matter for single word strings. I hope this helps.