fix build error on CentOS 7 (2009)

roles/soctools-server/tasks/main.yml

 ---
 # tasks file for docker-host
-
 - name: Install required packages
-  yum: 
-    name: ["yum-utils","device-mapper-persistent-data","lvm2","epel-release","rsync",] 
+  yum:
+    name: ["yum-utils","device-mapper-persistent-data","lvm2","epel-release","rsync"]
     state: latest
   when: ansible_distribution == 'CentOS' or ansible_distribution == 'Red Hat Enterprise Linux'
-
 - name: Add Docker repository
   get_url:
     url: https://download.docker.com/linux/centos/docker-ce.repo
     dest: /etc/yum.repos.d/docker-ce.repo
     mode: 0644
   when: ansible_distribution == 'CentOS' or ansible_distribution == 'Red Hat Enterprise Linux'
-
 - name: Install required packages
-  yum: 
-    name: ["docker-ce","docker-ce-cli","containerd.io","python-pip","unzip","firewalld"] 
+  yum:
+    name: ["docker-ce","docker-ce-cli","containerd.io","python-pip","unzip","firewalld","python-docker-py"]
     state: latest
     validate_certs: no
   when: ansible_distribution == 'CentOS' or ansible_distribution == 'Red Hat Enterprise Linux'
-
 - name: Install pip packages
   pip:
-    name: ["docker-py>1.10.0"," pexpect>=3.3"]
-
+    name: ["pexpect==3.3"]
 - name: Set sysctl parameters
   sysctl:
     name: "{{item.key}}"
@@ -33,19 +28,16 @@
     sysctl_set: yes
   with_items:
     - "{{sysctlconfig}}"
-
 - name: Configure fw
   ansible.posix.firewalld:
     rich_rule: "rule family=ipv4 source address={{ soctools_network }} accept"
     permanent: yes
     state: enabled
-
 - name: Reload firewalld
   systemd:
     state: restarted
     daemon_reload: yes
     name: firewalld
-
 - name: Start Docker service
   systemd:
     name: docker